An All-Purpose Preparation of Oxime Carbonates and Resultant Insights Into the Chemistry of Alkoxycarbonyloxyl Radicals

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Electronic Supplementary Information

An all-purpose preparation of oxime carbonates and resultant insights into the chemistry of alkoxycarbonyloxyl radicals.

Roy T. McBurney,* Andrew D. Harper, Alexandra M. Z. Slawin and John C. Walton.*

School of Chemistry, University of St. Andrews, EaStChem, St. Andrews,

Fife, KY16 9ST, UK.

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Table of Contents

General Experimental Section S3

Scheme S1. General one-pot procedure for the synthesis of oxime carbonates. S4

Scheme S2. General two-pot procedure for the synthesis of oxime carbonates. S4

Scheme S3. Chloroformate synthesis of oxime carbonates. S5

Synthesis and Experimental Section S6

Figure S1. The X-ray crystal structure of 5e. S18

Table S1. Crystal data and structure refinement for 5e. S18

Figure S2. The X-ray crystal structure of 9a. S19

Table S2. Crystal data and structure refinement for 9a. S19

UV Photolyses of Oxime Carbonates S20

EPR Spectroscopy S25

EPR spectra S26

Computational Methods S31

DFT Optimised Structures and Energies S31

References S40

1H and 13C NMR spectra of novel compounds S42

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General Experimental Section

All reagents and solvents were purchased from either Sigma Aldrich or Alfa Aesar and used

without further purification. Toluene and tetrahydrofuran were distilled over sodium and

dichloromethane was distilled over calcium hydride. Benzaldehyde oxime, acetophenone oxime, 4-

methoxyacetophenone oxime, and benzophenone oxime were prepared according to the literature

procedure,1 as was 4-(1H-indol-3-yl)butan-2-one.2 1-Phenylpent-4-en-1-ol was prepared in an

analogous fashion to the method reported by Studer;3 1H NMR and 13C NMR spectra were

consistent with literature values.4 Column chromatography was carried out using Silica 60A

(particle size 40-63 µm, Silicycle, Canada) as the stationary phase, and TLC was performed on

precoated silica gel plates (0.20 mm thick, Sil G UV254, Macherey-Nagel, Germany) and observed

under UV light. 1H and 13C NMR spectra were recorded on Bruker AV III 500, Bruker AV II 400

and Bruker AV 300 instruments. Chemical shifts are reported in parts per million (ppm) from low

to high frequency and referenced to the residual solvent resonance. Coupling constants (J) are

reported in hertz (Hz). Standard abbreviations indicating multiplicity were used as follows: s =

singlet, d = doublet, t = triplet, dd = double doublet, q = quartet, m = multiplet, b = broad. Melting

points (M.p.) were determined using a Sanyo Gallenkamp apparatus and are reported uncorrected.

Mass spectrometry was carried out at the EPSRC National Mass Spectrometry Service Centre,

Swansea, UK.

One-Pot CDI Oxime Carbonate General Procedure5

1,1-Carbonyldiimidazole (CDI) (1.0 equiv) was dissolved in THF (20 cm3) at 0 °C, alcohol (1

equiv.) in THF (10 cm3) was added dropwise and the solution stirred at 0 °C for 1 h then allowed to

warm to rt for another hour. In a second flask oxime (1 equiv.) was dissolved in THF (20 cm3) at 0

°C and sodium hydride was added (0.3 equiv.), the suspension was stirred for 5 min. The imidazole

intermediate mixture was then added slowly to the oxime/sodium hydride flask and stirred at 0 °C

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for 30 min before being allowed to warm to rt for a further 2 h. The solvent was removed under

reduced pressure and the crude residue was redissolved in EtOAc (100 cm3) and washed with

3 NH4Cl (3 × 100 cm ), dried over MgSO4, filtered and purified by column chromatography

(CH2Cl2/Pet Ether 40:60 (1:1) as eluent).

Scheme S1. General one-pot procedure for the synthesis of oxime carbonates. Reagents and conditions: i) R1OH, CDI,

THF, O °C to rt, 2 h; oxime, NaH, THF, O °C to rt, 2 h.

Two-Pot CDI Oxime Carbonate General Procedure6

To a 0 °C solution of 1,1-carbonyldimiidazole (3 equiv.) in THF (30 cm3) was added alcohol (1

equiv.). The reaction was stirred and allowed to warm to rt over 2 h. The solvent was removed

under reduced pressure and the crude residue was re-dissolved in EtOAc (100 cm3) and washed

3 with NH4Cl (3 × 100 cm ), dried over MgSO4, filtered and concentrated under reduced pressure. To

a solution of oxime (1.5 equiv.) in THF (20 cm3) at 0 °C, pre-treated with sodium hydride (0.3

equiv.), was added a THF solution (10 cm3) of the imidiazole intermediate. The reaction mixture

was stirred at 0 °C for 30 min and allowed to warm to rt and stirred for 18 h. The solvent was

removed under reduced pressure and the crude residue was re-dissolved in EtOAc (100 cm3) and

3 washed with NH4Cl (3 × 100 cm ), dried over MgSO4, filtered and purified by column

chromatography (CH2Cl2/Pet Ether 40:60 (1:1) as eluent). (For the cases where the imidazole

carboxylate intermediate was characterised, its spectral data immediately follows the

characterisation data for the resultant oxime carbonate.)

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Scheme S2. General two-pot procedure for the synthesis of oxime carbonates. Reagents and conditions: i) R1OH, CDI,

THF, O °C to rt, 2 h; ii) oxime, NaH, THF, O °C to rt, 18 h.

Chloroformate Synthesis of Oxime Carbonates General Procedure

3 To a stirred 0 °C solution of oxime (1.0 equiv.) and pyridine (1.0 equiv.) in CH2Cl2 (25 cm ) was

added dropwise chloroformate (1.0 equiv.). The solution was allowed to warm to rt over 18 h. The

3 3 reaction mixture was diluted with CH2Cl2 (75 cm ) and washed with 1 M HCl (100 cm ), sat. aq.

3 3 NHCO3 (100 cm ) and brine (100 cm ). The organic layer was dried over MgSO4, filtered,

concentrated under reduced pressure and purified by column chromatography (gradient elution Pet

Ether 40:60 to CH2Cl2).

Scheme S3. Chloroformate synthesis of oxime carbonates. Reagents and conditions: i) R1OC(O)Cl, oxime, pyridine,

CH2Cl2, O °C to rt, 18 h.

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Synthesis and Experimental Section

Benzaldehyde O-phenoxycarbonyl oxime

Prepared from phenyl chloroformate (0.68 cm3, 5.42 mmol), benzaldehyde oxime (0.547 g, 4.52

mmol) and pyridine (0.44 cm3, 5.42 mmol) to give a colourless oil (0.255 g, yield = 22%). 1H NMR

(300 MHz, CDCl3, 299 K):  = 7.26‒7.31 (m, 3H, HAr), 7.39‒7.54 (m, 5H, HAr), 7.77 (dd, J = 1.6

13 Hz, 7.9 Hz, 2H, Ha), 8.45 (s, 1H, Hb); C NMR (75 MHz, CDCl3, 297 K):  = 121.0, 126.3, 128.5,

129.0, 129.6, 129.6, 132.0, 150.9, 152.1, 156.5; LR-ESIMS: m/z = 242 [MH]+; HR-ESIMS: m/z =

242.0813 (calcd. for C14H12NO3, 242.0812).

Benzaldehyde O-((benzyloxy)carbonyl) oxime - 5a

Prepared from benzyl chloroformate (0.63 cm3, 4.42 mmol), benzaldehyde oxime (0.446 g, 3.69

mmol) and pyridine (0.35 cm3, 4.42 mmol) to give a colourless crystalline powder, 0.648 g, yield =

1 69%. M.p. = 58‒61 °C; H NMR (400 MHz, CDCl3, 297 K):  = 5.31 (s, 2H, Ha), 7.34‒7.50 (m,

13 8H, HAr), 7.72 (d, J = 9.6 Hz, 2H, Hc), 8.34 (s, 1H, Hb); C NMR (75 MHz, CDCl3, 297 K):  =

70.7, 128.8, 129.1 (× 2), 129.2, 129.3, 130.2, 132.2, 135.2, 154.2, 156.3; LR-ESIMS: m/z = 256

+ [MH] ; HR-ESIMS: m/z = 256.0970 (calcd. for C15H14NO3, 256.0968).

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Acetophenone O-((benzyloxy)carbonyl) oxime - 5b

Chloroformate Route: Prepared from benzyl chloroformate (0.45 cm3, 3.16 mmol), acetophenone

oxime (0.355 g, 2.63 mmol) and pyridine (0.25 cm3, 3.16 mmol) to give a colourless crystalline

powder, 0.648 g, yield = 87%.

CDI One-Pot Route: Prepared from benzyl alcohol (0.50 cm3, 4.83 mmol), CDI (0.783 g, 4.83

mmol), acetophenone oxime (0.652 g, 4.83 mmol) and sodium hydride (0.035 g, 1.45 mmol) to give

a colourless crystalline powder, 0.597 g, yield = 46%.

CDI Two-Pot Route: Prepared from benzyl alcohol (0.50 cm3, 4.83 mmol), CDI (2.348 g, 14.5

mmol), acetophenone oxime (0.979 g, 7.25 mmol), sodium hydride (0.035 g, 1.44 mmol) to give a

colourless crystalline powder, 0.861 g, yield = 63%.

1 M.p. = 53‒56 °C; H NMR (400 MHz, CDCl3, 294 K):  = 2.39 (s, 3H, Hb), 5.31 (s, 2H, Ha), 7.36‒

13 7.47 (m, 8H, HAr), 7.74 (d, J = 8.3 Hz, 2H, Hc); C NMR (100 MHz, CDCl3, 295 K):  = 14.4,

70.2, 127.0, 128.6, 128.7 (× 2), 128.8, 130.6, 134.6, 134.9, 153.9, 162.7; LR-ESIMS: m/z = 270

+ [MH] ; HR-ESIMS: m/z = 270.1126 (calcd. for C16H16NO3, 270.1125).

1 Benzyl 1H-imidazole-1-carboxylate - 4b: H NMR (400 MHz, CDCl3, 296 K):  = 5.42 (s, 2H,

Hd), 7.06 (d, J = 1.0 Hz, 1H, Hg), 7.11 (d, J = 1.0 Hz, 1H, Hf), 7.40‒7.46 (m, 5H, Ha,b,c), 8.15 (s, 1H,

13 He); C NMR (100 MHz, CDCl3, 297 K):  = 69.9, 117.2, 128.8, 128.9, 129.2, 130.7, 134.0, 135.1,

137.2.

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Benzaldehyde O-((1-phenylethoxy)carbonyl) oxime - 5c

CDI Two-Pot Route: Prepared from 1-phenyl ethanol (0.25 cm3, 2.05 mmol), CDI (1.000 g, 6.17

mmol), benzaldehyde oxime (0.372 g, 3.07 mmol) and sodium hydride (0.015 g, 0.62 mmol) to give

1 a colourless solid, 0.294 g, yield = 51%. M.p. = 74‒76 °C; H NMR (500 MHz, CDCl3, 295 K):  =

1.68 (d, J = 6.6 Hz, 3H, Ha), 5.90 (q, J = 6.6 Hz, 1H, Hb), 7.31‒7.49 (m, 8H, HAr), 7.71 (d, J = 7.0

13 Hz, 2H, Hd), 8.33 (s, 1H, Hc); C NMR (100 MHz, CDCl3, 295 K):  = 22.0, 126.3, 128.4 (× 2),

+ 128.6 (× 2), 128.9, 129.9, 131.7, 140.4, 153.1, 155.7; LR-ESIMS: m/z = 287 [MNH4] ; HR-ESIMS:

m/z = 287.1392 (calcd. for C16H19N2O3, 287.1390).

1 1-phenylethyl 1H-imidazole-1-carboxylate - 4c: H NMR (400 MHz, CDCl3, 294 K):  = 1.73 (d,

J = 6.6 Hz, 3H, Ha), 6.07 (q, J = 6.6 Hz, 1H, Hb), 7.06 (d, J = 1.0 Hz, 1H, He), 7.11 (d, J = 1.0 Hz,

13 1H, Hd), 7.33‒7.44 (m, 5H, HAr), 8.15 (s, 1H, Hc); C NMR (100 MHz, CDCl3, 295 K):  = 21.9,

117.2, 126.2, 128.8, 128.9, 130.6, 135.1, 137.1, 139.6, 148.0; LR-ESIMS: m/z = 217 [MH]+; HR-

ESIMS: m/z = 217.0973 (calcd. for C12H13N2O2, 217.0972).

Acetophenone O-((1-phenylethoxy)carbonyl) oxime - 5d

CDI Two-Pot Route: Prepared from 1-phenyl ethanol (0.25 cm3, 2.05 mmol), CDI (1.000 g, 6.17

mmol), acetophenone oxime (0.415 g, 3.07 mmol), sodium hydride (0.015 g, 0.62 mmol) to give a

1 colourless solid, 0.355 g, yield = 65%. M.p. = 45‒48 °C; H NMR (300 MHz, CDCl3, 296 K):  =

1.69 (d, J = 6.6 Hz, 3H, Ha), 2.39 (s, 3H, Hc), 5.91 (q, J = 6.6 Hz, 1H, Hb), 7.30‒7.46 (m, 8H, HAr),

13 7.73 (dd, J = 6.6 Hz, 2H, Hd); C NMR (75 MHz, CDCl3, 298 K):  = 14.4, 22.0, 126.3, 126.4,

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127.0, 128.3, 128.6 (× 2), 130.6, 134.7, 140.6, 153.4, 162.4; LR-ESIMS: m/z = 284 [MH]+; HR-

ESIMS: m/z = 284.1212 (calcd. for C17H18NO3, 284.1281).

1-(4-Methoxyphenyl)ethanone O-benzyloxycarbonyl oxime - 5e

Prepared from benzyl chloroformate (0.62 cm3, 4.39 mmol), 4-methoxyacetophenone oxime (0.604

g, 3.66 mmol) and pyridine (0.35 cm3, 4.39 mmol) to give a colourless solid, 1.010 g, yield = 92%.

1 M.p. = 92 °C; H NMR (400 MHz, CDCl3, 296 K):  = 2.35 (s, 3H, Hd), 3.84 (s, 3H, Ha), 5.30 (s,

13 2H, He), 6.91 (d, J = 8.9 Hz, 2H, Hb), 7.36‒7.47 (m, 5H, Hf,g,h), 7.71 (d, J = 8.9 Hz, 2H, Hc); C

NMR (75 MHz, CDCl3, 298 K):  = 14.5, 55.8, 70.5, 114.3, 127.2, 129.0, 129.1 (× 2), 129.1, 135.4,

154.4, 162.0, 162.5; LR-ESIMS: m/z = 300 [MH]+; HR-ESIMS: m/z = 300.1232 (calcd. for

C17H18NO4, 300.1230).

Benzophenone O-benzyloxycarbonyl oxime - 5f

Prepared from benzyl chloroformate (0.29 cm3, 2.01 mmol), benzophenone oxime (0.323 g, 1.67

mmol) and pyridine (0.16 cm3, 2.01 mmol) to give colourless solid, 0.518 g, yield = 94%. M.p. = 92

1 °C; H NMR (300 MHz, CDCl3, 297 K):  = 5.25 (s, 2H, Ha), 7.31‒7.47 (m, 13H, HAr), 7.57 (d, J =

13 8.6 Hz, 2H, Hb); C NMR (75 MHz, CDCl3, 298 K):  = 70.6, 128.7, 128.8, 129.0, 129.1, 129.1,

129.4, 129.5, 130.2, 131.3, 132.5, 135.0, 135.3, 154.5, 164.9; LR-ESIMS: m/z = 354 [MNa]+; HR-

ESIMS: m/z = 354.1106 (calcd. for C21H17NO3Na, 354.1101).

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Acetophenone O-(((1-phenylpent-4-en-1-yl)oxy)carbonyl) oxime – 5g

CDI One-Pot Route: Prepared from 1-phenylpent-4-en-1-ol3,4 (0.533 g, 3.29 mmol), CDI (0.533 g,

3.29 mmol), acetophenone oxime (0.772 g, 3.29 mmol) and sodium hydride (0.024 g, 0.99 mmol) to

1 give a colourless oil, 0.578 g, yield = 54%. H NMR (300 MHz, CDCl3, 296 K):  = 1.94‒2.02 (m,

1H, Hd), 2.10‒2.26 (m, 3H, Hd’,e), 2.39 (s, 3H, Hb), 4.99‒5.09 (m, 2H, Hg), 5.73‒5.90 (m, 2H, Hc,f),

13 7.24‒7.43 (m, 8H, HAr), 7.73 (dd, J = 1.4 Hz, 7.9 Hz, 2H, Ha); C NMR (100 MHz, CDCl3, 298 K):

 = 9.1, 24.4, 30.0, 75.1, 110.3, 121.6, 121.8, 123.2, 123.3 (×2), 125.3, 129.4, 132.0, 134.2, 148.2,

+ 157.2; LR-ESIMS: m/z = 324 [MH] ; HR-ESIMS: m/z = 324.1593 (calcd. for C20H22NO3,

324.1594).

Acetophenone O-(biphenyl-2-ylmethoxy)carbonyl oxime - 5h

CDI One-Pot Route: Prepared from biphenylmethanol (0.184 g, 1.0 mmol), CDI (0.162 g, 1.0

mmol), acetophenone oxime (0.235 g, 1.0 mmol) and sodium hydride (0.007 g, 0.3 mmol) to give a

1 colourless solid, 0.251 g, yield = 73%. M.p. = 87 °C; H NMR (400 MHz, CDCl3, 296 K):  = 2.39

(s, 3H, Hb), 5.25 (s, 2H, Hc), 7.34‒7.46 (m, 11 H, HAr), 7.62‒7.64 (m, 1H, Hd), 7.74 (dd, J = 1.3 Hz,

13 7.9 Hz, 2H, Ha); C NMR (100 MHz, CDCl3, 297 K):  = 14.4, 68.2, 127.0, 127.5, 127.7, 128.3,

128.6, 128.8, 129.3, 130.1, 130.3, 130.6, 132.3, 134.6, 140.2, 142.7, 153.8, 162.6; LR-ESIMS: m/z

+ = 368 [MNa] ; HR-ESIMS: m/z = 368.1258 (calcd. for C22H19NO3Na, 368.1257).

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4-(1H-Indol-3-yl)butan-2-ol

To a solution of 4-(1H-indol-3-yl)butan-2-one2 (1.007 g, 5.82 mmol, 1.0 equiv.) in THF (50 cm3)

and MeOH (0.1 cm3) was added sodium borohydride (0.885 g, 23.30 mmol, 4.0 equiv.), the

resulting suspension was stirred for 18 h. The solvent was removed under reduced pressure and the

crude residue redissolved in EtOAc (100 cm3), washed with 1M HCl (100 cm3), saturated aqueous

3 3 NaHCO3 (100 cm ) and brine (100 cm ), dried over MgSO4 and concentrated under reduced

pressure to give the title compound as a colourless oil, 1.057 g, yield = 96%, which was used

without further purification. The 1H NMR spectrum was consistent with that reported in the

7 1 literature. H NMR (300 MHz, CDCl3, 297 K):  = 1.26 (d, J = 6.3 Hz, 3H, Ha), 1.50‒1.56 (br, 1H,

Hb), 1.85‒1.92 (m, 2H, He), 2.79‒2.96 (m, 2H, Hd), 3.85‒3.96 (m 1H, Hc), 6.98 (d, J = 2.3 Hz, 1H,

Hf), 7.09‒7.23 (m, 2H, Hi,j), 7.35 (d, J = 7.9 Hz, 1H, Hk), 7.63 (d, J = 7.8 Hz, 1H, Hh), 7.96‒8.09

(br, 1H, Hg).

Acetophenone O-(((4-(1H-indol-3-yl)butan-2-yl)oxy)carbonyl) oxime – 5i

CDI One-Pot Route: Prepared from 4-(1H-indol-3-yl)butan-2-ol (1.019 g, 5.82 mmol), CDI (0.942

g, 5.82 mmol), acetophenone oxime (1.368 g, 5.82 mmol) and sodium hydride (0.042 g, 1.75 mmol)

1 to give a tan coloured oil, 1.440 g, yield = 74%. H NMR (400 MHz, CDCl3, 296 K):  = 1.42 (d, J

= 6.2 Hz, 3H, He), 1.94‒2.06 (m, 1H, Hg), 2.12‒2.25 (m, 1H, Hg’), 2.43 (s, 3H, Hd), 2.80‒2.99 (m,

2H, Hh), 5.00‒5.10 (m, 1H, Hf), 7.00 (d, J = 2.3 Hz, 1H, Hi), 7.13 (td, J = 1.3 Hz, 7.0 Hz, 1H, Hml),

7.19 (td, J = 1.3 Hz, 7.0 Hz, 1H, Hlm), 7.35 (d, J = 7.7 Hz, 1H, Hk), 7.38‒7.46 (m, 3H, Ha,b), 7.62 (d,

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13 J = 7.7 Hz, 1H, Hn), 7.77 (dd, J = 1.5 Hz, 7.9 Hz, 2H, Hc), 8.00‒8.10 (br, 1H, Hj); C NMR (100

MHz, CDCl3, 297 K):  = 14.9, 20.5, 21.5, 36.5, 111.6, 115.6, 119.1, 119.6, 122.0, 122.4, 127.4,

127.7, 129.0, 131.0, 135.2, 136.8, 154.2, 162.8, 203.3; LR-ESIMS: m/z = 351 [MH]+; HR-ESIMS:

m/z = 351.1701 (calcd. for C21H23N2O3, 351.1703).

Benzaldehyde O-((allyloxy)carbonyl) oxime - 6a

Prepared from benzaldehyde oxime (0.320 g, 2.64 mmol), pyridine (0.21 cm3, 2.64 mmol) and

allylchloroformate (0.28 cm3, 2.64 mmol) to give a colourless oil, 0.269 g, yield = 50%. 1H NMR

(400 MHz, CDCl3, 300 K):  = 4.77 (dt, J = 1.4 Hz, 5.8 Hz, 2H, Hc), 5.33 (dd, J = 1.2 Hz, 10.4 Hz,

1H, Ha), 5.43 (dd, J = 1.4 Hz, 17.2 Hz, 1H, Ha’), 5.95‒6.04 (m, 1H, Hb), 7.40‒7.49 (m, 3H, HAr),

13 7.73 (d, J = 6.9 Hz, 2H, He), 8.35 (s, 1H, Hd); C NMR (100 MHz, CDCl3, 300 K):  = 69.1, 119.7,

128.4, 128.9, 129.8, 131.1, 131.8, 153.6, 155.9; LR-ESIMS: m/z = 206 [MH]+; HR-ESIMS: m/z =

206.0813 (calcd. for C11H12NO3, 206.0812).

Acetophenone O-((allyloxy)carbonyl) oxime - 6b

Prepared form acetophenone oxime (0.567 g, 4.2 mmol), pyridine (0.34 cm3, 4.2 mmol) and

allylchloroformate (0.34 cm3, 4.2 mmol) to give a colourless crystalline solid, 0.777 g, yield = 84%.

1 M.p. = 44‒46 °C; H NMR (300 MHz, CDCl3, 300 K):  = 2.40 (s, 3H, Hd), 4.77 (dt, J = 1.3 Hz,

5.9 Hz, 2H, Hc), 5.32 (dd, J = 1.2 Hz, 10.3 Hz, 1H, Ha), 5.43 (dd, J = 1.4 Hz, 17.2 Hz, 1H, Ha’),

13 5.94‒6.07 (m, 1H, Hb), 7.37‒7.46 (m, 3H, HAr), 7.74 (dd, J = 1.5 Hz, 7.8 Hz, 2H, He); C NMR

(100 MHz, CDCl3, 300 K):  = 14.4, 69.0, 119.6, 127.0, 128.6, 130.6, 131.3, 134.6, 153.7, 162.7;

+ LR-ESIMS: m/z = 220 [MH] ; HR-ESIMS: m/z = 220.0969 (calcd. for C12H14NO3, 220.0968).

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Benzophenone O-allyloxycarbonyl oxime - 6c

Prepared from benzophenone oxime (0.503 g, 2.55 mmol), allyl chloroformate (0.26 cm3, 2.45

mmol) and pyridine (0.21 cm3, 2.60 mmol) to give a colourless solid, 0.667 g, yield = 97%. M.p. =

1 67‒69 °C; H NMR (400 MHz, CDCl3, 296 K):  = 4.71 (d, J = 5.9 Hz, 2H, Hc), 5.27 (dd, J = 1.2

Hz, 10.4 Hz, 1H, Ha), 5.36 (dd, J = 1.4 Hz, 17.2 Hz, 1H, Ha’), 5.95 (m, 1H, Hb), 7.33‒7.39 (m, 4H,

13 HAr), 7.43‒7.48 (m, 4H, HAr), 7.56‒7.59 (m, 2H, Hd); C NMR (100 MHz, CDCl3, 297 K):  =

(both isomers) 69.1, 119.6, 128.3, 128.4, 129.0, 129.1, 129.8, 130.9, 131.3, 132.1, 134.6, 153.8,

+ 164.5; LR-ESIMS: m/z = 304 [MNa] ; HR-ESIMS: m/z = 304.0942 (calcd. for C17H15NO3Na,

304.0944).

4-Methoxyacetophenone O-((allyloxy)carbonyl) oxime - 6d

Prepared from 4-methoxyacetophenone oxime (0.502 g, 3.04 mmol), allyl chloroformate (0.32 cm3,

3. 95 mmol) and pyridine (0.25 cm3, 3.11 mmol) to give a colourless solid, 0.746 g, yield = 98%.

1 M.p. = 53‒56 °C; H NMR (400 MHz, CDCl3, 296 K):  = 2.36 (s, 3H, Hd), 3.83 (s, 3H, Hg), 4.75

(d, J = 5.94 Hz, 2H, Hc), 5.32 (dd, J = 1.2 Hz, 10.4 Hz, 1H, Ha), 5.42 (dd, J = 1.4 Hz, 17.3 Hz, 1H,

13 Ha’), 6.00 (m, 1H, Hb), 6.90 (d, J = 8.9 Hz, 2H, Hf), 7.70 (d, J = 8.9 Hz, 2H, He); C NMR (75

MHz, CDCl3, 297 K):  = 14.5, 55.8, 69.3, 114.3, 119.9, 127.2, 128.9, 131.8, 154.2, 162.0, 162.5;

+ LR-ESIMS: m/z = 250 [MH] ; HR-ESIMS: m/z = 250.1077 (calcd. for C13H16NO4, 250.1074).

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Acetophenone O-allyloxycarbonothioyl oxime - 7

CDI Two-Pot Route: Prepared from allyl alcohol (0.38 cm3, 5.60 mmol), 1,1’-

thiocarbonyldiimidazole (3.011 g, 16.90 mmol), acetophenone oxime (1.014 g, 7.51 mmol), sodium

hydride (0.037 g, 1.50 mmol) to give a tan coloured oil, 0.584 g, yield = 44%. 1H NMR (400 MHz,

CDCl3, 296 K):  = 2.44 (s, 3H, Hd), 5.09 (dq, J = 1.3 Hz, 5.8 Hz, 2H, Hc), 5.36 (dq, J = 1.2 Hz,

10.4 Hz, 1H, Ha), 5.47 (dq, J = 1.3 Hz, 17.2 Hz, 1H, Ha’), 6.06 (qt, J = 5.8 Hz, 10.4 Hz, 17.2 Hz,

13 1H, Hb), 7.40‒7.49 (m, 3H, HAr), 7.76 (dd, J = 1.4 Hz, 8.0 Hz, 2H, He); C NMR (100 MHz,

CDCl3, 297 K):  = 14.8, 74.2, 119.9, 127.2, 128.7, 130.7, 130.9, 134.3, 163.4, 193.0; LR-

ASAPMS: m/z = 235 [M]+.

1 O-Allyl 1H-imidazole-1-carbothioate: H NMR (400 MHz, CDCl3, 296 K):  = 5.14 (dt, J = 1.2

Hz, 6.0 Hz, 2H, Hc), 5.40 (dq, J = 1.2 Hz, 10.4 Hz, 1H, Ha), 5.48 (dq, J = 1.2 Hz, 17.2 Hz, 1H, Ha’),

6.09 (qt, J = 6.0 Hz, 10.4 Hz, 17.2 Hz, 1H, Hb), 7.02 (s, 1H, Hf), 7.63 (s, 1H, He), 8.34 (s, 1H, Hd);

13 C NMR (100 MHz, CDCl3, 297 K):  = 73.7, 117.9, 120.9, 130.0, 130.9, 136.9, 183.9.

Acetophenone O-(cyclohex-2-enyloxy)carbonyl oxime - 8

CDI Two-Pot Route: Prepared from 2-cyclohexanol (0.34 cm3, 3.54 mmol), CDI (1.719 g, 10.61

mmol), acetophenone oxime (0.717 g, 5.32 mmol) and sodium hydride (0.026 g, 1.06 mmol) to give

1 a colourless oil, 0.569 g, yield = 62%. H NMR (400 MHz, CDCl3, 296 K):  = 1.61‒1.69 (m, 1H,

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Hb), 1.71‒1.84 (m, 1H, Hb’), 1.87‒2.05 (m, 3H, Ha,c), 2.07‒2.15 (m, 1H, Ha’), 2.37 (s, 3H, Hg),

5.26‒5.31 (m, 1H, Hf), 5.82‒5.86 (m, 1H, Hd), 5.99‒6.04 (m, 1H, He), 7.36‒7.44 (m, 3H, HAr), 7.73

13 (dd, J = 1.5 Hz, 7.9 Hz, 2H, Hh); C NMR (100 MHz, CDCl3, 297 K):  = 14.4, 18.6, 24.9, 28.2,

72.7, 124.8, 127.0, 128.6, 130.5, 133.8, 134.7, 153.7, 162.3; LR-ESIMS: m/z = 282 [MNa]+; HR-

ESIMS: m/z = 282.1100 (calcd. for C15H17NO3Na, 282.1101).

1 Cyclohex-2-enyl 1H-imidazole-1-carboxylate: H NMR (300 MHz, CDCl3, 296 K):  = 1.62‒2.19

(m, 6H, Ha,b,c), 5.41‒5.49 (m, 1H, Hf), 5.78‒5.86 (m, 1H, Hd), 6.04‒6.12 (m, 1H, He), 7.04 (s, 1H,

13 Hi), 7.41 (s, 1H, Hh), 8.12 (s, 1H, Hg); C NMR (75 MHz, CDCl3, 297 K):  = 18.9, 25.2, 28.5,

73.1, 117.5, 124.3, 130.9, 135.2, 137.5, 148.8; LR-ESIMS: m/z = 193 [MH]+; HR-ESIMS: m/z =

193.0971 (calcd. for C10H13N2O2, 193.0972).

Benzaldehyde O-((prop-2-yn-1-yloxy)carbonyl) oxime - 9a

Prepared form benzaldehyde oxime (0.274 g, 2.26 mmol), pyridine (0.18 cm3, 2.26 mmol) and

propargyl chloroformate (0.24 cm3, 2.26 mmol) to give a colourless crystalline solid, 0.054 g, yield

1 = 12%. M.p. = 96 °C; H NMR (400 MHz, CDCl3, 300 K):  = 2.58 (t, J = 2.5 Hz, 1H, Ha), 4.87 (d,

13 J = 2.5 Hz, 2H, Hb), 7.40‒7.50 (m, 3H, HAr), 7.72 (d, J = 6.9 Hz, 2H, Hd), 8.35 (s, 1H, Hc); C

NMR (100 MHz, CDCl3, 300 K):  = 55.9, 76.3, 76.6, 128.5, 129.0, 129.6, 131.9, 153.2, 156.4; LR-

+ ESIMS: m/z = 204 [MH] ; HR-ESIMS: m/z = 204.0655 (calcd. for C11H10NO3, 204.0655).

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Acetophenone O-(prop-2-yn-1-yloxy)carbonyl oxime - 9b

Prepared form acetophenone oxime (0.670 g, 4.96 mmol), pyridine (0.38 cm3, 4.96 mmol) and

propargyl chloroformate (0.53 cm3, 5.46 mmol) to give a colourless crystalline solid, 0.983 g, yield

1 = 91%. M.p. = 88 °C; H NMR (300 MHz, CDCl3, 300 K):  = 2.41 (s, 3H, Hc), 2.58 (t, J = 2.5 Hz,

1H, Ha), 4.88 (d, J = 2.5 Hz, 2H, Hb), 7.39‒7.47 (m, 3H, HAr), 7.74 (dd, J = 1.4 Hz, 8.0 Hz, 2H, Hd);

13 C NMR (100 MHz, CDCl3, 300 K):  = 14.5, 55.7, 55.8, 76.2, 127.1, 128.6, 130.8, 134.4, 153.3,

+ 163.2; LR-ESIMS: m/z = 218 [MH] ; HR-ESIMS: m/z = 218.0813 (calcd. for C12H12NO3,

218.0812).

Acetophenone O-((2-allylphenoxy)carbonyl) oxime - 10

CDI One-Pot Route: Prepared from 2-allyl phenol (0.65 cm3, 5.00 mmol), CDI (0.810 g, 5.00

mmol), acetophenone oxime (0.675 g, 5.00 mmol) and sodium hydride (0.036 g, 1.50 mmol) to give

1 a colourless oil, 0.392 g, yield = 26%. H NMR (300 MHz, CDCl3, 296 K):  = 2.50 (s, 3H, Hd),

3.46 (d, J = 6.6 Hz, 2H, Hi), 5.10‒5.18 (m, 2H, Hk), 5.99 (m, J = 6.6 Hz, 10.2 Hz, 16.8 Hz, 1H, Hj),

13 7.23‒7.35 (m, 4H, He,f,g,h), 7.42‒7.50 (m, 3H, Ha,b), 7.81 (dd, J = 1.4 Hz, 7.8 Hz, 2H, Hc); C NMR

(75 MHz, CDCl3, 298 K):  = 14.9, 34.8, 117.0, 122.3, 127.0, 127.5, 128.0, 129.1, 130.9, 131.2,

132.4, 134.8, 136.1, 149.6, 152.5, 163.7; LR-ESIMS: m/z = 296 [MH]+; HR-ESIMS: m/z =

296.1288 (calcd. for C18H18NO3, 296.1281).

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Acetophenone O-((cinnamyloxy)carbonyl) oxime - 11

Half of the crude mixture of acetophenone O-(((1-phenylallyl)oxy)carbonyl) oxime 13 (1.343 g)

was refluxed in toluene (30 cm3) for 5 days. The solvent was removed under reduced pressure and

the crude residue was purified by column chromatography (gradient elution, Pet Ether to

CH2Cl2:Pet Ether 1:1) to give the title compound as a colourless solid, 0.505 g, yield = 45% (w.r.t.

1 α-vinyl benzyl alcohol). M.p. = 70 °C. H NMR (400 MHz, CDCl3, 300 K):  = 2.32 (s, 3H, Hd),

4.85 (d, J = 6.6 Hz, 2H, Hc), 6.29 (dd, J = 6.6 Hz, 15.9 Hz, 1H, Hb), 6.68 (d, J = 15.9 Hz, 1H, Ha),

13 7.17‒7.38 (m, 8H, HAr), 7.66 (d, J = 8.0 Hz, 2H, He); C NMR (100 MHz, CDCl3, 300 K):  =

14.4, 69.1, 122.1, 126.8, 127.0, 128.3, 128.6, 128.7, 130.7, 134.6, 135.7, 136.0, 153.8, 162.7; LR-

+ ESIMS: m/z = 318 [MNa] ; HR-ESIMS: m/z = 318.1103 (calcd. for C18H17NO3, 318.1101).

Acetophenone O-(((1-phenylallyl)oxy)carbonyl) oxime - 13

Prepared from α-vinyl benzyl alcohol 23 (1.00 cm3, 7.61 mmol), CDI (3.698 g, 22.8 mmol),

acetophenone oxime (1.541 g, 11.41 mmol) and sodium hydride (0.055 g, 2.28 mmol) to give a tan

coloured oil, 2.686 g, the product was used without further purification. 1H NMR (400 MHz,

CDCl3, 297 K):  = 2.30 (s, 3H, Hd), 5.33‒5.45 (m, 2H, Hc), 6.07‒6.16 (m, 1H, Hb), 6.26‒6.27 (d, J

13 = 6.1 Hz, 1H, Ha), 7.34‒7.46 (m, 8H, HAr), 7.63‒7.65 (m, 2H, He); C NMR (100 MHz, CDCl3,

300 K):  = 12.2, 80.7, 118.2, 126.1, 127.0, 127.4, 128.5, 128.6, 128.7, 129.2, 130.6, 135.4, 153.3,

+ 162.6; LR-ESIMS: m/z = 318 [MNa] ; HR-ESIMS: m/z = 318.1100 (calcd. for C18H17NO3,

318.1101).

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d N a O N f e c b O 1 1-Phenylallyl 1H-imidazole-1-carboxylate: H NMR (400 MHz, CDCl3, 294 K):  = 5.38‒5.44

(m, 2H, Hc), 6.09‒6.17 (m, 1H, Hb), 6.42 (d, J = 6.1 Hz, 1H, Ha), 7.07 (s, 1H, Hf), 7.30‒7.45 (m,

13 6H, HAr,e), 8.17 (s, 1H, Hd); C NMR (75 MHz, CDCl3, 295 K):  = 80.6, 117.1, 118.9, 127.3,

128.9, 129.1, 130.7, 134.6, 137.1, 137.1, 147.9.

Figure S1. The X-ray crystal structure of 5e.

Table S1. Crystal data and structure refinement for 5e.

Identification code 5e CCDCcode 896683

Empirical Formula C17H17NO4 Formula Weight 299.33 Crystal Colour, Habit colourless, prism Crystal Dimensions 0.120 × 0.050 × 0.030 mm Crystal System monoclinic Lattice Type Primitive Lattice Parameters a = 11.892(3) Å β = 95.099(8)° b = 7.5168(13) Å c = 17.092(4) Å Volume 1521.8(5) Å3

Space Group P21/n (#14) Z value 4 Density (calculated) 1.306 g/cm3 F(000) 632.00 μ(CuKα) 7.715 cm-1 Diffractometer Saturn70 Radiation CuKα (λ = 1.54187 Å) Voltage, Current 40 kV, 20 mA Temperature -100.0 °C Detector Aperture 70 × 70 mm

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ω oscillation Range 1.0 - 0.0° Pixel Size 0.034 mm 2θmax 135.1°

No. of Reflections Measured Total: 16358, Unique: 2628 (Rint = 0.0806) Corrections Lorentz-polarization Structure Solution Direct Methods Refinement Full-matrix least-squares on F2 2 2 2 Function Minimized Σ w (Fo - Fc ) Least Squares Weights w = 1/ [σ2(Fo2) + (0.1051 · P)2 + 2.9953 · P ] where P = (Max(Fo2,0) + 2Fc2)/3

2θmax cutoff 135.1° Anomalous Dispersion All non-hydrogen atoms No. Observations (All reflections) 2628 No. Variables 199 Reflection/Parameter Ratio 13.21 Residuals: R1 (I>2.00σ(I)) 0.1086 Residuals: R (All reflections) 0.1272 Residuals: wR2 (All reflections) 0.3165 Goodness of Fit Indicator 1.465 Max Shift/Error in Final Cycle 0.004 MaximumpeakinFinalDiff.Map 0.32e/Å3 Minimum peak in Final Diff. Map -0.33 e /Å3

Figure S2. The X-ray crystal structure of 9a.

Table S2. Crystal data and structure refinement for 9a.

Identification code 9a CCDCcode 896684

Empirical Formula C11H9NO3 Formula Weight 203.20 Crystal Colour, Habit colourless, prism Crystal Dimensions 0.100 × 0.100 × 0.100 mm Crystal System orthorhombic Lattice Type Primitive Lattice Parameters a = 19.168(13) Å b = 6.189(5) Å c = 8.461(5) Å Volume 1003.7(12) Å3 Space Group Pnma (#62) Z value 4 Density (calculated) 1.345 g/cm3

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F(000) 424.00 μ(MoKα) 0.992 cm-1 Diffractometer Mercury70 Radiation MoKα (λ = 0.71075 Å) Voltage, Current 50 kV, 16 mA Temperature -180.0 °C Detector Aperture 70 × 70 mm Pixel Size 0.068 mm 2θmax 50.7°

No. of Reflections Measured Total: 5804, Unique: 1006 (Rint = 0.1655) Corrections Lorentz-polarization Absorption (trans. factors: 0.247 - 0.990) Secondary Extinction (coefficient: 1.38700e-001) Structure Solution Charge Flipping (Superflip) Refinement Full-matrix least-squares on F2 Function Minimized Σ w (Fo2 - Fc2)2 Least Squares Weights w = 1/ [σ2(Fo2) + (0.2000 · P)2 + 0.0000 · P] where P = (Max(Fo2,0) + 2Fc2)/3 2θmax cutoff 50.7° Anomalous Dispersion All non-hydrogen atoms No. Observations (All reflections) 1006 No. Variables 92 Reflection/Parameter Ratio 10.93 Residuals: R1 (I>2.00σ(I)) 0.1057 Residuals: R (All reflections) 0.1145 Residuals: wR2 (All reflections) 0.2968 Goodness of Fit Indicator 1.134 Max Shift/Error in Final Cycle 0.132 MaximumpeakinFinalDiff.Map 0.70e/Å3 Minimum peak in Final Diff. Map -0.41 e /Å3

UV Photolyses of Oxime Carbonates

Scheme S4. UV photolyses of oxime carbonate 5g.

A solution of oxime carbonate 5g (0.060 g, 0.19 mmol) in benzene (2 cm3) was irradiated at RT for

4 h. 1H NMR product analysis (w.r.t. MAP) revealed: 41% alcohol.

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A solution of oxime carbonate 5g (0.060 g, 0.19 mmols) and 4-methoxyacetophenone (0.060 g,

0.27 mmol) in t-BuOH (2 cm3) was irradiated at RT for 4 h. 1H NMR product analysis (w.r.t. MAP)

revealed: 52% alcohol.

A solution of oxime carbonate 5g (0.040 g, 0.12 mmols) and 4-methoxyacetophenone (0.040 g,

3 1 0.27 mmol) in PhCF3 (2 cm ) was heated at 70 °C and irradiated for 3 h. H NMR product analysis

(w.r.t. MAP) revealed: 30% alcohol.

A solution of oxime carbonate 5g (0.048 g, 0.15 mmol) and 4-methoxyacetophenone (0.048 g, 0.32

mmol) in t-BuOH (2 cm3) was heated at 70 °C and irradiated for 3 h. 1H NMR product analysis

(w.r.t. MAP) revealed: 39% alcohol.

Table S3. UV photolyses results for oxime carbonate 5g.

entry solvent temperature time / h yield alcohol 1 Benzene RT 4 41% 2 t-BuOH RT 4 52%

3 PhCF3 70 °C 3 30% 4 t-BuOH 70 °C 3 39%

Scheme S5. UV photolysis of oxime carbonate 5h

A solution of oxime carbonate 5h (0.038 g, 0.11 mmol) and 4-methoxyacetophenone (0.038 g, 0.25

3 1 mmol) in PhCF3 (2.5 cm ) was irradiated for 3 h. H NMR product analysis (w.r.t. MAP) revealed:

22% 2-biphenylmethanol; <5% unreacted oxime carbonate 5h.

A solution of oxime carbonate 5h (0.047 g, 0.14 mmol) and 4-methoxyacetophenone (0.047 g, 0.31

3 1 mmol) in PhCF3 (2 cm ) was heated at 70 °C and irradiated for 4.5 h. H NMR product analysis

(w.r.t. MAP and CH2Br2) revealed: 35% 2-biphenylmethanol; <5% unreacted 5h.

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A solution of oxime carbonate 5h (0.047 g, 0.14 mmol) and 4-methoxyacetophenone (0.047 g, 0.31

mmol) in toluene (2 cm3) was heated at 70 °C and irradiated for 4.5 h. 1H NMR product analysis

(w.r.t. MAP and CH2Br2) revealed: 40% 2-biphenylmethanol; <5% unreacted 5h.

Scheme S6. UV photolysis of indole oxime carbonate 5i.

A solution of oxime carbonate 5i (0.067 g, 0.20 mmol) and 4-methoxy acetophenone (0.067 g, 0.45

mmol) in toluene (2 cm3) was heated at 80 °C and irradiated for 3 h. 1H NMR product analysis

(w.r.t. MAP) revealed: 11% unreacted 5i; 42% 4-(1H-indol-3-yl)butan-2-ol.

Scheme S7. UV photolysis of allyl oxime carbonates 6b-d, 7. Reagents and conditions: MAP, Tol, UV.

0 °C: A solution of oxime carbonate 6b (0.053 g, 0.24 mmol) and 4-methoxy acetophenone (MAP)

(0.053 g, 0.35 mmol) in toluene (2 cm3) was irradiated for 5 h at 0 °C. 1H NMR product analysis

(w.r.t. MAP) revealed: 44% unreacted oxime carbonate 6b; 14% 4-methyl-1,3-dioxolan-2-one 30a;

6% allyl alcohol.

RT: A solution of oxime carbonate 6b (0.061 g, 0.28 mmol) and 4-methoxy acetophenone (MAP)

(0.061 g, 0.41 mmol) in toluene (2 cm3) was irradiated for 4 h at RT. 1H NMR product analysis

(w.r.t. MAP) revealed: 22% unreacted 6b; 18% 4-methyl-1,3-dioxolan-2-one 30a; 6% allyl alcohol.

4-Methyl-1,3-dioxolan-2-one was purified by column chromatography (gradient elution, Pet Ether

to CH2Cl2) to yield the 4-methyl-1,3-dioxolan-2-one 30a as a tan coloured oil, 0.005 g, yield =

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1 8 1 18%. H NMR was consistent with data reported in the literature. H NMR (400 MHz, CDCl3, 296

K):  = 1.50 (d, J = 6.3 Hz, 3H, Ha), 4.03 (t, J = 8.1 Hz, 1H, Hc), 4.55 (t, J = 8.1 Hz, 1H, Hc’), 4.85

(m, 1H, Hb).

RT: A solution of oxime carbonate 6c (0.058 g, 0.21 mmol) and 4-methoxy acetophenone (MAP)

(0.063 g, 0.42 mmol) in toluene (2 cm3) was irradiated for 5 h at RT. 1H NMR product analysis

(w.r.t. MAP) revealed: 24% unreacted oxime carbonate 17c; 19% 4-methyl-1,3-dioxolan-2-one 30a.

RT: A solution of oxime carbonate 6d (0.050 g, 0.21 mmol) and 4-methoxy acetophenone (MAP)

(0.050 g, 0.33 mmol) in toluene (2 cm3) was irradiated for 5 h at RT. 1H NMR product analysis

(w.r.t. MAP) revealed: 43% unreacted oxime carbonate 6d; 14% 4-methyl-1,3-dioxolan-2-one 30a.

A solution of oxime thiocarbonate 7 (0.053 g, 0.23 mmol) and 4-methoxy acetophenone (MAP)

(0.053 g, 0.35 mmol) in toluene (2 cm3) was irradiated for 4 h at RT. 1H NMR product analysis

(w.r.t. CH2Br2, 0.142 mmol) revealed: 9% unreacted 7; 5% 4-methyl-1,3-dioxolane-2-thione 30b;

25% allyl alcohol.

Scheme S8. UV photolyis of oxime carbonate 8.

A solution of acetophenone O-(cyclohex-2-enyloxy)carbonyl oxime 8 (0.050 g, 0.19 mmol) and 4-

methoxyacetophenone (0.049 g, 0.33 mmol) in toluene (3 cm3) was irradiated for 5 h. 1H NMR

product analysis (w.r.t. MAP) revealed: 13% unreacted 8; 22% hexahydrobenzo[1,3]dioxol-2-one.

A solution of acetophenone O-(cyclohex-2-enyloxy)carbonyl oxime (0.108 g, 0.42 mmol) and 4-

methoxyacetophenone (0.108 g, 0.72 mmol) in toluene (3 cm3) was irradiated for 4 h. 1H NMR

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product analysis (w.r.t. MAP) revealed: 22% hexahydrobenzo[1,3]dioxol-2-one; 7% 2-cyclohexen-

1-ol.

Scheme S9. UV photolysis of allylphenoxy oxime carbonate 10.

A solution of allylphenoxy oxime carbonate 10 (0.080 g, 0.271 mmol) and 4-methoxyacetophenone

(0.080 g, 0.533 mmol) in toluene (2 cm3) was irradiated for 3 h at RT. 1H NMR product analysis

(w.r.t. MAP) revealed: 11% unreacted 10; 55% 2-allylphenol.

Scheme S10. UV photolysis of oxime carbonate 11.

A solution of allylphenoxy oxime carbonate 11 (0.053 g, 0.179 mmol) and 4-methoxyacetophenone

(0.053 g, 0.353 mmol) in toluene (2 cm3) was irradiated for 3 h at RT. 1H NMR product analysis

(w.r.t. MAP) revealed no identifiable products or by-products.

O O UV N O Scheme S11. UV photolysis of oxime carbonate 13.

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A solution of allylphenoxy oxime carbonate 13 (0.058 g, 0.179 mmol) and 4-methoxyacetophenone

(0.058 g, 0.387 mmol) in toluene (3 cm3) was irradiated for 3 h at RT. 1H NMR product analysis

(w.r.t. MAP) revealed no identifiable products or by-products.

EPR Spectroscopy

EPR spectra were obtained with a Bruker EMX 10/12 spectrometer fitted with a rectangular

ER4122 SP resonant cavity and operating at 9.5 GHz with 100 kHz modulation. Stock solutions of

each oxime carbonate (2 to 15 mg) and MAP (1 equiv. wt/wt) in tert-butylbenzene or benzene (0.5

cm3) were prepared and sonicated if necessary. An aliquot (0.2 cm3), to which any additional

reactant had been added, was placed in a 4 mm o.d. quartz tube, de-aerated by bubbling nitrogen for

15 min, and photolysed in the resonant cavity by unfiltered light from a 500 W super pressure

mercury arc lamp. Solutions in cyclopropane were prepared on a vacuum line by distilling in the

cyclopropane, degassing with three freeze-pump-thaw cycles and finally flame sealing the tubes. In

all cases where spectra were obtained, hfs were assigned with the aid of computer simulations using

the Bruker SimFonia and NIEHS Winsim2002 software packages. For kinetic measurements,

precursor samples were used mainly in 'single shot' experiments, i.e. new samples were prepared for

each temperature and each concentration to minimize sample depletion effects. EPR signals were

digitally filtered and double integrated using the Bruker WinEPR software and radical

concentrations were calculated by reference to the double integral of the signal from a known

concentration of the stable radical DPPH [1  10-3 M in PhMe], run under identical conditions, as

described previously. The majority of EPR spectra were recorded with 2.0 mW power, 0.8 Gpp

modulation intensity and gain of ca. 106.

EPR Spectra

Scheme S12. Radicals detected upon UV photolyses of allyl oxime carbonates 6a-d, 7.

Figure S3. Top spectrum from 6b at 217 K in t-BuPh showing iminyl radical PhMeC=N• and 21 (X=O); bottom

spectrum from 6a at 230 K in t-BuPh showing iminyl radical PhHC=N• and 21 (X=O).

Figure S4. Top: experimental EPR spectrum from allyl oxime thiocarbonate 7 in t-BuPh at 220 K showing iminyl

radical PhMeC=N• and cyclised 2-thiono-1,3-dioxolanyl-4-methyl radical 22; bottom: simulation with parameters listed

in Table 3 of main text

Scheme S13. Radicals detected upon UV photolyses of acetophenone O-((cyclohex-2-en-1-yloxy)carbonyl) oxime 19.

Figure S5. a) Experimental EPR spectrum from acetophenone O-((cyclohex-2-en-1-yloxy)carbonyl) oxime 8 in t-BuPh

at 265 K showing iminyl PhMeC=N• and bicyclic hexahydrobenzo[d][1,3]dioxol-2-one-4-yl radical 23; b) simulation

with the parameters from Table 3 in the main text.

Scheme S14. Radicals detected upon UV photolyses of oxime carbonate 11.

Figure S6. Full black line experimental EPR spectrum from oxime carbonate 11 in t-BuPh at 220 K (NB a peroxyl

signal was digitally removed to the left and an F-centre (trapped electron in quartz EPR tube) is visible at ~3390 G).

Red line: simulation of radical 24 with parameters from Table 3.

Table S4. Reference parameters from DPPH standard. [DPPH] 1.00E-03 Gain DPPH 2.00E+03 D.Int DPPH 76 temp DPPH 300 Actual T 302.258 F[Spiro] 1 F[Im] 1

Table S5. Kinetic EPR data for CO2 loss from PhCHMeOC(O)ON=CHPh precursor 5c and MAP with UV in t-BuPh. Results from using [Spiro]/[Im] ratio. 3 -1 Dial Actual scans Gain [Sp]/[Im] D Int D Int [Spiro] [Im] Im-Spiro kd/2kt logkd/2kt log2kt 10 /T log  log  log2kt log kd kd s Temp /K / K Spiro Im M M M n-C7 n-C7 t-BuPh t-BuPh t-BuPh 210 210.55 5 2.0E+06 9.60E-01 11.92 12 3.04E-08 3.17E-08 1.27E-09 1.32E-09 -8.879 9.292 4.750 0.17 1.06 8.402 -4.770E-01 3.33E-01

220 220.74 7 2.0E+06 9.20E-01 11.6 12.69 2.31E-08 2.51E-08 2.01E-09 2.18E-09 -8.661 9.400 4.530 0.08 0.85 8.635 -2.615E-02 9.42E-01

230 230.93 5 2.0E+06 9.20E-01 9.76 12.42 3.31E-08 3.60E-08 2.88E-09 3.13E-09 -8.505 9.498 4.330 0.00 0.66 8.834 3.286E-01 2.13E+00

240 241.12 16 2.0E+06 9.20E-01 18.68 20.7 1.80E-08 1.96E-08 1.56E-09 1.70E-09 -8.769 9.588 4.147 -0.08 0.51 9.004 2.342E-01 1.71E+00

250 251.31 5 2.0E+06 8.20E-01 6.32 10.8 2.79E-08 3.40E-08 6.12E-09 7.47E-09 -8.127 9.671 3.979 -0.15 0.37 9.150 1.024E+00 1.06E+01

260 261.50 8 2.0E+06 6.60E-01 7.2 12.72 1.72E-08 2.61E-08 8.86E-09 1.34E-08 -7.872 9.747 3.824 -0.21 0.26 9.277 1.405E+00 2.54E+01

270 271.69 8 2.0E+06 4.90E-01 6.96 10.46 1.09E-08 2.23E-08 1.14E-08 2.32E-08 -7.635 9.818 3.681 -0.27 0.16 9.388 1.753E+00 5.66E+01

280 281.88 11 2.0E+06 4.10E-01 5.68 9.84 6.48E-09 1.58E-08 9.33E-09 2.27E-08 -7.643 9.883 3.548 -0.33 0.07 9.484 1.841E+00 6.94E+01

290 292.07 10 2.0E+06 2.40E-01 4.8 10.24 4.50E-09 1.87E-08 1.42E-08 5.94E-08 -7.226 9.944 3.424 -0.38 -0.01 9.569 2.342E+00 2.20E+02

Table S6. Kinetic EPR data for CO2 loss from BnOC(O)ON=CHPh precursor 5a and MAP with UV in t-BuPh. Results from using [Spiro]/[Im] ratio.

3 -1 Dial Actual T [Im] [Spiro]/ [Spiro] Im-Spiro kd/2kt logkd/2kt log2kt 10 /T log  log  log2kt log kd kd s

Temp /K / K M [Im] M M n-C7 n-C7 t-BuPh t-BuPh t-BuPh

210 210.55 7.63E-08 0.98 7.48E-08 1.53E-09 1.56E-09 -8.807 9.292 4.750 0.17 1.06 8.402 -4.050E-01 3.94E-01

220 220.74 7.08E-08 0.923 6.53E-08 5.45E-09 5.91E-09 -8.229 9.400 4.530 0.08 0.85 8.635 4.064E-01 2.55E+00

230 230.93 5.96E-08 0.65 3.87E-08 2.08E-08 3.21E-08 -7.494 9.498 4.330 0.00 0.66 8.834 1.340E+00 2.19E+01

240 241.12 3.45E-08 0.48 1.65E-08 1.79E-08 3.73E-08 -7.428 9.588 4.147 -0.08 0.51 9.004 1.576E+00 3.77E+01

240 241.12 3.03E-08 0.48 1.45E-08 1.57E-08 3.28E-08 -7.484 9.588 4.147 -0.08 0.51 9.004 1.519E+00 3.31E+01

250 251.31 4.50E-08 0.34 1.53E-08 2.97E-08 8.73E-08 -7.059 9.671 3.979 -0.15 0.37 9.150 2.091E+00 1.23E+02

260 261.50 2.92E-08 0.28 8.17E-09 2.10E-08 7.50E-08 -7.125 9.747 3.824 -0.21 0.26 9.277 2.152E+00 1.42E+02

280 281.88 2.75E-08 0.22 6.05E-09 2.15E-08 9.75E-08 -7.011 9.883 3.548 -0.33 0.07 9.484 2.473E+00 2.97E+02

290 292.07 1.63E-08 0.18 2.93E-09 1.34E-08 7.42E-08 -7.130 9.944 3.424 -0.38 -0.01 9.569 2.439E+00 2.75E+02

300 302.26 2.49E-08 0.11 2.74E-09 2.22E-08 2.02E-07 -6.696 10.001 3.308 -0.43 -0.07 9.643 2.947E+00 8.86E+02

Computational Methods

Radical ground-state calculations were carried out using the Gaussian 03 program package.9

Becke’s three-parameter hybrid exchange potential (B3)10 was used with the LYP correlation

functional, B3LYP. This method has previously described the chemistry of iminyl radicals

accurately. The standard split-valence 6-31+G(d) basis set was initially employed.

Geometries were fully optimised for all model compounds. Optimised structures were

characterised as minima or saddle points by frequency calculations. The experimental kinetic

and spectroscopic data was all obtained in the non-polar hydrocarbon solvents tert-

butylbenzene or cyclopropane. Solvent effects, particularly differences in solvation between

the neutral reactants and neutral transition states, are therefore expected to be minimal. In

view of this, no attempt was made to computationally model the effect of the solvent.

DFT Optimised Structures and Energies

Table S7. Spiro radical 16 optimised geometry: UB3LYP/6-311+G(2d,p) E = -534.8507054 H. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -2.295664 1.227332 -0.164861 2 6 0 -0.944819 1.251142 0.048900 3 6 0 -0.945707 -1.251442 0.047200 4 6 0 -2.296534 -1.226366 -0.166541 5 6 0 -3.000103 0.000807 -0.273633 6 1 0 -2.839570 2.164257 -0.255930 7 1 0 -0.403467 2.191879 0.116779 8 1 0 -0.405021 -2.192653 0.113754 9 1 0 -2.841106 -2.162778 -0.258900 10 1 0 -4.071536 0.001304 -0.448497 11 6 0 -0.130049 -0.000534 0.175760 12 6 0 0.778799 -0.001697 1.453247 13 1 0 0.625047 -0.895675 2.063625 14 1 0 0.623988 0.890458 2.065996 15 8 0 2.125259 -0.000238 0.970904 16 6 0 2.152564 0.000360 -0.390469 17 8 0 3.155067 0.001103 -1.046987 18 8 0 0.894767 -0.000165 -0.895723

Table S8. Formate radical HOC(O)O UB3LYP/6-31+G(d), E = -264.338117801 AU.

Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -0.054666 -0.000501 0.000080 2 8 0 -0.899010 -0.939414 -0.000012 3 8 0 1.243704 -0.287237 -0.000038 4 1 0 1.757043 0.543099 0.000118 5 8 0 -0.523325 1.159140 -0.000026

Table S9. Transition State (TS) for CO2 loss from formate radical, UB3LYP/6-31+G(d), E = -264.305299191. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 0.364846 0.135899 0.003012 2 8 0 -0.208296 1.212615 -0.011374 3 8 0 -1.178588 -0.703318 -0.102473 4 1 0 -1.673760 -0.520111 0.725016 5 8 0 1.322469 -0.546207 0.020961

Table S10. EtOC(O)O radical UB3LYP/6-311+G(2d,p), E = -343.067582235. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 1.213554 0.488541 0.000151 2 1 0 1.097009 1.111970 0.886979 3 1 0 1.096878 1.112353 -0.886390 4 6 0 -1.091098 -0.057660 0.000114 5 8 0 -2.054983 -0.871394 -0.000023 6 8 0 -1.420654 1.143830 -0.000119 7 8 0 0.143805 -0.510903 0.000015 8 6 0 2.524517 -0.262042 -0.000108 9 1 0 2.614646 -0.891339 -0.886543 10 1 0 3.349501 0.453435 -0.000013 11 1 0 2.614776 -0.891723 0.886042

 Table S11. TS for CO2 loss from EtOC(O)O UB3LYP/6-311+G(2d,p), E = -343.047081623. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -1.182615 -0.639242 -0.266277 2 1 0 -1.482932 -1.673483 -0.033646 3 1 0 -0.802705 -0.626469 -1.291666 4 6 0 1.303105 0.145697 0.000768 5 8 0 0.996152 1.317523 -0.054561 6 8 0 2.103601 -0.699475 -0.180153 7 8 0 -0.142475 -0.390947 0.656094 8 6 0 -2.358161 0.305112 -0.065126 9 1 0 -2.053414 1.329600 -0.282054 10 1 0 -3.169916 0.027835 -0.741146 11 1 0 -2.723228 0.256304 0.961280

Table S12. t-BuOC(O)O radical UB3LYP/6-31+G(d), E = -421.601173354. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -1.103701 0.823024 1.275699 2 1 0 -0.947496 0.198141 2.161638 3 1 0 -0.377487 1.640004 1.288095 4 1 0 -2.108467 1.255953 1.338528 5 6 0 -0.996675 -0.014687 -0.000002 6 6 0 -2.011279 -1.157590 -0.000484 7 1 0 -1.888765 -1.785193 -0.888904 8 1 0 -1.889129 -1.785619 0.887686 9 1 0 -3.027411 -0.748929 -0.000594 10 6 0 -1.103164 0.823634 -1.275344 11 1 0 -0.376911 1.640593 -1.287059 12 1 0 -0.946631 0.199169 -2.161519 13 1 0 -2.107887 1.256634 -1.338364 14 8 0 0.307877 -0.750360 0.000067 15 6 0 1.472044 -0.136573 0.000189 16 8 0 1.676150 1.100426 -0.000032 17 8 0 2.531828 -0.837266 -0.000017

Table S13. TS for CO2 loss from t-BuOC(O)O radical UB3LYP/6-31+G(d), E = -421.581836272. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 0.668857 -0.349850 1.498034 2 1 0 0.021930 0.413972 1.942203 3 1 0 0.180210 -1.324699 1.593500 4 1 0 1.600268 -0.374839 2.073638 5 6 0 0.978176 -0.025925 0.034419 6 6 0 1.617763 1.364527 -0.132172 7 1 0 1.805426 1.579029 -1.188516 8 1 0 0.950341 2.133797 0.267582 9 1 0 2.568680 1.398360 0.411238 10 6 0 1.875810 -1.114938 -0.606911 11 1 0 1.409634 -2.100699 -0.520990 12 1 0 2.056022 0.896761 -1.663264 13 1 0 2.835438 -1.128637 -0.077782 14 6 0 -1.718179 0.010920 -0.143240 15 8 0 -2.257591 -1.042953 -0.022546 16 8 0 -1.794434 1.225345 -0.024203 17 8 0 -0.193289 -0.058383 -0.795550

Table S14. AllylOC(O)O radical 19, UB3LYP/6-31+G(d), E = -381.042619081. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 0.668857 -0.349850 1.498034 2 8 0 0.021930 0.413972 1.942203 3 8 0 0.180210 -1.324699 1.593500

4 8 0 1.600268 -0.374839 2.073638 5 6 0 0.978176 -0.025925 0.034419 6 1 0 1.617763 1.364527 -0.132172 7 1 0 1.805426 1.579029 -1.188516 8 6 0 0.950341 2.133797 0.267582 9 1 0 2.568680 1.398360 0.411238 10 6 0 1.875810 -1.114938 -0.606911 11 1 0 1.409634 -2.100699 -0.520990 12 1 0 -0.193289 -0.058383 -0.795550

 Table S15. TS for CO2 loss from allylOC(O)O radical 19, UB3LYP/6-31+G(d), E = -381.020982285. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 1.689265 0.176429 -0.064844 2 8 0 2.233366 -0.911423 0.039018 3 8 0 0.203282 -0.391112 -0.576689 4 8 0 1.767160 1.359426 0.036145 5 6 0 -0.748907 -0.639792 0.457742 6 1 0 -1.146670 -1.651131 0.327562 7 1 0 -0.279119 -0.541570 1.443369 8 6 0 -1.819864 0.405530 0.243826 9 1 0 -1.525502 1.430523 0.458438 10 6 0 -3.044216 0.112510 -0.208506 11 1 0 -3.336218 -0.904943 -0.459609 12 1 0 -3.800630 0.883931 -0.326848

Table S16. Radical PhCHMeOC(O)O 15c, UB3LYP/6-31+G(d), E = -574.025742529. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -2.680173 -0.726364 -0.987889 2 6 0 -1.413096 -0.188939 -1.232411 3 6 0 -0.658923 0.358763 -0.187937 4 6 0 -1.184750 0.350009 1.112482 5 6 0 -2.445491 -0.195245 1.359512 6 6 0 -3.198255 -0.730791 0.308972 7 1 0 -3.254360 -1.149911 -1.807706 8 1 0 -1.005403 -0.204462 -2.240879 9 1 0 -0.601088 0.755997 1.934717 10 1 0 -2.840181 -0.203942 2.372209 11 1 0 -4.180159 -1.154531 0.502985 12 6 0 0.690820 0.980018 -0.478109 13 1 0 1.000795 0.727681 -1.495849 14 8 0 1.710795 0.427778 0.442697 15 6 0 2.296845 -0.706771 0.106650 16 8 0 3.136036 -1.233193 0.898432 17 8 0 2.117844 -1.337975 -0.960916 18 6 0 0.744227 2.489082 -0.272740 19 1 0 0.492121 2.752294 0.759421

20 1 0 1.743667 2.873757 -0.500490 21 1 0 0.019985 2.971665 -0.937288

 Table S17. TS for CO2 loss from radical PhCHMeOC(O)O 15c, UB3LYP/6-31+G(d), E = -574.006040808. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 2.369930 -1.538783 0.283393 2 6 0 1.079250 -1.056185 0.492639 3 6 0 0.772930 0.292972 0.233146 4 6 0 1.767793 1.136781 -0.284875 5 6 0 3.059130 0.651744 -0.490590 6 6 0 3.363376 -0.685237 -0.207522 7 1 0 2.598572 -2.579572 0.495512 8 1 0 0.297092 -1.721192 0.849341 9 1 0 1.545004 2.174488 -0.510159 10 1 0 3.829486 1.316251 -0.872627 11 1 0 4.369526 -1.060253 -0.375645 12 6 0 -0.655762 0.764482 0.490357 13 1 0 -1.023679 0.301901 1.414681 14 8 0 -1.344079 0.190320 -0.628855 15 6 0 -2.651188 -0.753635 -0.231990 16 8 0 -3.530579 0.078700 -0.382051 17 8 0 -2.378347 -1.876299 0.070782 18 6 0 -0.891416 2.270982 0.529881 19 1 0 -0.620314 2.742644 -0.418989 20 1 0 -1.951976 2.464435 0.713829 21 1 0 -0.303925 2.720813 1.338414

Table S18. Radical BnOC(O)O 15a, UB3LYP/6-31+G(d), E = -534.706276187. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -2.780182 -1.236783 0.123537 2 6 0 -1.443381 -1.187008 -0.275739 3 6 0 -0.786475 0.044220 -0.406940 4 6 0 -1.488837 1.226262 -0.137138 5 6 0 -2.826560 1.179396 0.261204 6 6 0 -3.473503 -0.052705 0.392540 7 1 0 -3.280534 -2.196531 0.221335 8 1 0 -0.905507 -2.108987 -0.485624 9 1 0 -0.986718 2.185940 -0.238349 10 1 0 -3.362727 2.102132 0.466472 11 1 0 -4.515218 -0.090081 0.700432 12 6 0 0.654870 0.094542 -0.823843 13 1 0 0.919653 -0.731501 -1.488825 14 1 0 0.908661 1.040463 -1.308885 15 8 0 1.481710 -0.024480 0.392104 16 6 0 2.790877 -0.018122 0.222957 17 8 0 3.552518 -0.119381 1.233178

18 8 0 3.383465 0.081330 -0.876034

 Table S19. TS for CO2 loss from radical BnOC(O)O 15a, UB3LYP/6-31+G(d), E = -534.686689163. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -2.232691 1.451185 0.039252 2 6 0 -0.956429 0.967035 0.324641 3 6 0 -0.716162 -0.418155 0.331141 4 6 0 -1.751026 -1.306879 0.004353 5 6 0 -3.027039 -0.819165 -0.276799 6 6 0 -3.268869 0.560016 -0.259739 7 1 0 -2.417707 2.521804 0.043182 8 1 0 -0.140967 1.653636 0.536289 9 1 0 -1.559280 -2.376888 -0.013220 10 1 0 -3.831917 -1.511180 -0.509304 11 1 0 -4.262396 0.938371 -0.485478 12 6 0 0.672989 -0.930593 0.656404 13 1 0 1.087237 -0.457767 1.553628 14 1 0 0.675782 -2.019814 0.770460 15 8 0 1.438843 -0.590228 -0.495718 16 6 0 2.807118 0.312764 -0.177400 17 8 0 3.621857 -0.592720 -0.203271 18 8 0 2.599538 1.477271 -0.019345

‡ ‡ Figure S7. Plot of Activation Energies (E a - experimental and E - DFT computed) vs. DFT computed reaction enthalpies H298 for CO2 loss from ROC(O)O radicals. Red squares: experimental data. Blue circles: DFT computed data.

Table S20. 2-Oxo-1,3-dioxolan-4-yl-methyl radical 21, UB3LYP/6-311+G(2d,p), E = -381.170257965. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -1.120665 -0.163631 -0.027325 2 8 0 -2.221982 -0.566897 -0.216329 3 8 0 -0.691935 1.089444 -0.330939 4 8 0 -0.113352 -0.887563 0.526564 5 6 0 0.640482 1.284595 0.155240 6 1 0 1.222748 1.782880 -0.617498 7 1 0 0.600065 1.905610 1.051989 8 6 0 1.128771 -0.150425 0.452267

9 1 0 1.578234 -0.203704 1.451650 10 6 0 2.022214 -0.738262 -0.571756 11 1 0 2.885453 -0.183569 -0.915626 12 1 0 1.906838 -1.774751 -0.855431

Table S21. TS for ring closure to 2-oxo-1,3-dioxolan-4-yl-methyl radical 21, UB3LYP/6-311+G(2d,p), E = - 381.144538739. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -1.150100 -0.132783 -0.004441 2 8 0 -2.314504 -0.341124 -0.272723 3 8 0 -0.524115 1.008089 -0.383135 4 8 0 -0.444270 -0.988881 0.671300 5 6 0 0.744051 1.225238 0.256930 6 1 0 1.261102 1.954482 -0.367195 7 1 0 0.567749 1.667478 1.238986 8 6 0 1.534034 -0.053657 0.389527 9 1 0 1.886945 -0.311112 1.380970 10 6 0 1.935953 -0.790501 -0.669118 11 1 0 1.645494 -0.533082 -1.681396 12 1 0 2.518187 -1.692230 -0.532286

Table S22. 2-Thio-1,3-dioxolan-4-yl-methyl radical 22, UB3LYP/6-311+G(2d,p), E = -704.117593880. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 0.761608 0.027335 -0.026459 2 8 0 0.268369 1.280806 -0.004134 3 8 0 -0.227366 -0.872195 -0.144462 4 6 0 -1.166365 1.230107 0.088188 5 1 0 -1.455739 1.386581 1.129903 6 1 0 -1.580055 2.018334 -0.536597 7 6 0 -1.508571 -0.179842 -0.401329 8 1 0 -1.649726 -0.200864 -1.483644 9 6 0 -2.612853 -0.851795 0.301458 10 1 0 -3.366779 -1.401912 -0.242275 11 1 0 -2.619389 -0.883100 1.383376 12 16 0 2.343797 -0.346422 0.072928

Figure S8. DFT computed rotational potential functions for radicals 21, 26 and 27.

45 40 35 30 G / )

a 25 t e B - 20 H ( a 15 10 5 0 -90 -70 -50 -30 -10 10 30 50 70 90 Theta/deg.

Figure S9. DFT computed a(H) values [UB3LYP/6-311+G(2d,p)] as a function of the dihedral angle theta () between the SOMO and the CH bond.

Table S23. Cyclopentylmethyl radical 26, UB3LYP/6-311+G(2d,p), E = -235.271710952. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -0.004178 -1.197215 0.174720 2 1 0 0.209128 -1.322217 1.241272

3 1 0 0.252878 -2.136467 -0.318392 4 6 0 0.826119 -0.001282 -0.360849 5 1 0 0.768092 -0.014912 -1.455738 6 6 0 2.248820 0.004540 0.053867 7 1 0 2.507135 0.062501 1.105506 8 1 0 3.058052 -0.071159 -0.659670 9 6 0 -1.472549 -0.780783 -0.039414 10 1 0 -2.127072 -1.202889 0.725425 11 1 0 -1.834233 -1.152597 -1.000909 12 6 0 -1.477953 0.775472 -0.026758 13 1 0 -2.109314 1.177757 0.767638 14 1 0 -1.875951 1.161732 -0.967718 15 6 0 -0.005478 1.201306 0.151988 16 1 0 0.239690 2.128056 -0.369940 17 1 0 0.222909 1.357962 1.211211

Table S24. Tetrahydrofuranylmethyl radical 27, UB3LYP/6-311+G(2d,p), E = -271.182610301. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 8 0 -0.052687 -1.144240 -0.108944 2 6 0 0.064742 1.197832 0.187993 3 1 0 -0.121767 1.299847 1.260071 4 1 0 -0.150030 2.153895 -0.290481 5 6 0 -0.802932 0.052859 -0.383982 6 1 0 -0.866117 0.182931 -1.476282 7 6 0 -2.165635 -0.063322 0.174929 8 1 0 -2.338866 -0.682711 1.044362 9 1 0 -2.984009 0.503977 -0.247380 10 6 0 1.480311 0.677484 -0.075677 11 1 0 2.233311 1.125294 0.574473 12 1 0 1.769895 0.873331 -1.111194 13 6 0 1.320602 -0.827444 0.163673 14 1 0 1.539044 -1.095066 1.203137 15 1 0 1.957501 -1.432039 -0.486771

Table S25. 2-Phenylpyrrolomethyl radical 28, UB3LYP/6-31+G(d), E = -481.097360008. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -1.645993 1.162228 0.209068 2 6 0 -0.858119 0.029552 -0.054145 3 6 0 -1.497707 -1.210986 -0.235433 4 6 0 -2.884418 -1.310965 -0.155956 5 6 0 -3.660654 -0.175418 0.108939 6 6 0 -3.037370 1.060335 0.292581 7 1 0 -1.175945 2.130652 0.354712 8 1 0 -0.886814 -2.084733 -0.438289 9 1 0 -3.364535 -2.275673 -0.300420 10 1 0 -4.743074 -0.255691 0.170754

11 1 0 -3.631490 1.946866 0.499516 12 6 0 0.616786 0.128056 -0.138805 13 6 0 1.371022 1.447703 -0.010718 14 6 0 2.779109 -0.516494 -0.300645 15 6 0 2.801532 1.043493 -0.414961 16 1 0 1.311688 1.814393 1.023631 17 1 0 0.953503 2.232223 -0.651737 18 1 0 3.243041 -0.963231 -1.198309 19 1 0 3.569393 1.498468 0.217581 20 1 0 3.002246 1.340156 -1.450519 21 7 0 1.357793 -0.907583 -0.300709 22 6 0 3.466213 -1.057019 0.912193 23 1 0 3.032951 -1.885625 1.462602 24 1 0 4.482080 -0.747640 1.142736

Table S26. 1-Methyl-pyrrolidin-2-on-5-methyl radical (model for 29), E = -364.603412866. Centre Atomic Atomic Coordinates (Angstroms) Number Number Type XYZ 1 6 0 -0.239854 -1.698600 0.155775 2 6 0 1.084644 -1.322695 -0.524216 3 6 0 1.177817 0.235534 -0.360399 4 1 0 -0.775910 -2.515379 -0.335087 5 1 0 -0.107104 -1.981190 1.207891 6 1 0 1.045799 -1.563108 -1.592863 7 1 0 1.956420 -1.825196 -0.097198 8 1 0 1.579948 0.676079 -1.284348 9 7 0 -0.231435 0.614753 -0.217998 10 6 0 -1.072096 -0.418656 0.107457 11 8 0 -2.272583 -0.318436 0.333969 12 6 0 2.014752 0.683073 0.795328 13 1 0 3.078774 0.861062 0.668644 14 1 0 1.602988 0.700650 1.800759 15 6 0 -0.667992 1.995780 -0.278519 16 1 0 -1.752146 2.011199 -0.148158 17 1 0 -0.200365 2.596250 0.512137 18 1 0 -0.411314 2.437238 -1.250098

References

1. R. T. McBurney, A. M. Z. Slawin, L. A. Smart, Y. Yu and J. C. Walton, Chem.

Commun. 2011, 47, 7974.

2. V. Kumar, S. Kaur and S. Kumar, Tetrahedron Lett. 2006, 47, 7001.

3. B. Janza, A. Studer, J. Org. Chem. 2005, 6991.

4. I. Peñafiel, I. M. Pastor and M. Yus, Tetrahedron 2010, 66, 2928.

5. G. Bertolini, G. Pavich and B. Vergani, J. Org. Chem. 1998, 63, 6031.

6. T. Werner, A. G. M. Barrett, J. Org. Chem. 2006, 71, 4302.

7. P. López-Alvarado, J. Steinhoff, S. Miranda, C. Avendaño and J. C. Menéndez,

Tetrahedron 2009, 65, 1660.

8. B. R. Buckley, A. P. Patel and K. G. U. Wijayantha, Chem. Commun. 2011, 47,

11888.

9. Gaussian 03, Revision A.1, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E.

Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N.

Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci,

M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara,

K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.

Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, C. Adamo, J.

Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C.

Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J.

Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas,

D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A.

G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P.

Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng,

A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong,

C. Gonzalez, and J. A. Pople, Gaussian, Inc., Pittsburgh PA, 2003.

10. A. D. Becke, J. Chem. Phys. 1993, 98, 5648.

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