Supporting Information Copper-Catalyzed Semihydrogenation of Internal Alkynes with Molecular Hydrogen Takamichi Wakamatsu, Kazunori Nagao, Hirohisa Ohmiya*, and Masaya Sawamura* Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan Table of Contents Instrumentation and Chemicals S1 Characterization Data for Alkynes S1–S2 Procedure for the Copper-Catalyzed Semihydrogenation of Alkynes S2 Characterization Data for Alkenes S3–S5 References S5 NMR Spectra S6–S31 Instrumentation and Chemicals NMR spectra were recorded on a JEOL ECX-400, operating at 400 MHz for 1H NMR and 100.5 13 1 13 MHz for C NMR. Chemical shift values for H and C are referenced to Me4Si and the residual solvent resonances, respectively. Mass spectra were obtained with Thermo Fisher Scientific Exactive, JEOL JMS-T100LP or JEOL JMS-700TZ at the Instrumental Analysis Division, Equipment Management Center, Creative Research Institution, Hokkaido University. TLC analyses were performed on commercial glass plates bearing 0.25-mm layer of Merck Silica gel 60F254. Silica gel (Kanto Chemical Co., Silica gel 60 N, spherical, neutral) was used for column chromatography. Materials were obtained from commercial suppliers or prepared according to standard procedure unless otherwise noted. CuCl was purchased from Aldrich Chemical Co., stored under nitrogen, and used as it is. NatOBu, octane and 6-dodecyne 1a were purchased from TCI Chemical Co., stored under nitrogen, and used as it is. Diphenylacetylene 1j was purchased from Wako Chemical Co., stored under nitrogen, and used as it is. 1,4-Dioxane was purchased from Kanto Chemical Co., distilled from sodium/benzophenone and stored over 4Å molecular sieves under nitrogen. Alkynes 1b1, 1e2, 1f3, 1k4, 1l5 and 1m6 were known compounds. Alkyne 1c was prepared by THP protection of 3-octyn-1-ol. Alkyne 1d7 was prepared by the reaction between the corresponding lithium acetylide and 1-butyliodide. Alkyene 1g was prepared by Corey-Fuchs reaction with 2,6-dimethoxybenzaldehyde. Alkyne 1h was prepared by Sonogashira-Hagihara cross-coupling reaction between 1-decyne and methyl 4-iodobenzoate. Alkyne 1i was prepared by Sonogashira-Hagihara cross-coupling reaction between 1-nonyne and 4-bromoiodobenzene. [(SIMes)CuCl] was prepared according to the reported procedure.8 Characterization Data for Alkynes 2-(3-Octyn-1-yloxy)tetrahydro-2H-pyran (1c) S1 THPO C5H11 1c 1 Colorless Oil. H NMR (400MHz, CDCl3) δ 0.90 (t, J = 7.2 Hz, 3H), 1.34–1.63 (m, 8H), 1.72 (m, 1H), 1.83 (m, 1H), 2.14 (tt, J = 7.2, 2.4 Hz, 2H), 2.45 (tt, J = 7.2, 2.4 Hz, 2H), 3.48–3.55 (m, 2H), 13 3.79 (m, 1H), 3.89 (m, 1H), 4.65 (m, 1H). C NMR (100.5 MHz, CDCl3) δ 13.59, 18.38, 19.37, 20.19, 21.85, 25.42, 30.54, 31.03, 62.09, 66.20, 76.68, 81.27, 98.65. HRMS–ESI (m/z): [M+Na]+ calcd for C13H22O2Na, 233.15120; found, 233.15098. 1,3-Dimethoxy-2-(1-propyn-1-yl)benzene (1g) OMe Me 1g OMe 1 White solid. M.p. 106–108 ˚C. H NMR (400MHz, CDCl3) δ 2.19 (s, 3H), 3.88 (s, 6H), 6.52 (d, 13 J = 8.0 Hz, 2H), 7.21 (t, J = 8.0 Hz, 1H). C NMR (100.5 MHz, CDCl3) δ 5.2, 56.0, 71.5, 94.4, + 101.9, 103.4 128.7, 161.3. HRMS–EI (m/z): [M] calcd for C11H12O2, 176.08373; found, 173.08309. Methyl 4-(1-Decyn-1-yl)benzoate (1h) O C8H17 MeO 1h 1 Colorless Oil. H NMR (400MHz, CDCl3) δ 0.88 (t, J = 6.8 Hz, 3H), 1.22–1.39 (m, 8H), 1.40–1.50 (m, 2H), 1.57–1.63 (m, 2H), 2.42 (t, J = 7.2 Hz, 2H), 3.90 (s, 3H), 7.41 (d, J = 8.0 Hz, 13 2H), 7.95 (d, J = 8.0 Hz, 2H). C NMR (100.5 MHz, CDCl3) δ 14.09, 19.49, 22.64, 28.56, 28.92, 29.09, 29.18, 31.82, 52.12, 80.06, 94.01, 128.75, 128.93, 129.36, 131.43, 166.65. HRMS–APCI + (m/z): [M+H] calcd for C18H25O2, 273.18491; found, 273.18480. Procedure for the Copper-Catalyzed Semihydrogenation of Alkynes The reaction in eq. 1 is representative. In a glove box, [(SIMes)CuCl] (20.3 mg, 0.05 mmol) and t-BuONa (4.8 mg, 0.05 mmol) were placed in a Schlenk flask containing a magnetic stirring bar. Then, octane (0.8 mL), 1,4-dioxane (0.2 mL) and 6-dodecyne (1a) were added, and the Schlenk flask was sealed with a glass stopper and then removed from the glove box. The mixture was cooled to –196 ˚C. Finally, N2 atomosphere was replaced with H2 in a balloon. The resulting mixture was heated at 100 ˚C for 12 h. As the reaction proceeded, a small amount of black solid was precipitated. After 12 h stirring at 100˚C, hexane was added to the mixture. The mixture was filtered through a short plug of silica gel, which was then washed with hexane. The NMR yield (94%) and stereoselectivity (Z/E >99:1) of 2a were determined by the 1H NMR analysis (1,1,2,2-tetrachloroethane was used as an internal standard). The residue was purified by flash column chromatography (hexane) on silica gel to give 2a (70.7 mg, 0.42 mmol) in 84% isolated yield. S2 Characterization Data for Alkenes (Z)-6-Dodecene (2a) C5H11 C5H11 H H 2a The product 2a was purified by flash chromatography on silica gel (hexane) (84% isolated yield from 1a, Z/E >99:1). 2a was consistent with the the literature data.9 (Z)-1-Hexen-1-ylcyclohexane (2b) C5H11 H H 2b The product 2b was purified by flash chromatography on silica gel (hexane) (68% isolated yield from 1b, Z/E >99:1). 2b was consistent with the the literature data.10 (Z)-2-(3-Octen-1-yloxy)tetrahydro-2H-pyran (2c) THPO C5H11 H H 2c The product 2c was purified by flash chromatography on silica gel (0–5% EtOAc/hexane) (77% 1 isolated yield from 1c, Z/E >99:1). Colorless oil. H NMR (400MHz, CDCl3) δ 0.87–0.92 (m, 3H), 1.29–1.36 (m, 4H), 1.49–1.62 (m, 4H), 1.71 (m, 1H), 1.82 (m, 1H), 2.05 (q, J = 6.8 Hz, 2H), 2.35 (q, J = 6.8 Hz, 2H), 3.41 (dt, J = 9.6, 6.8 Hz, 1H), 3.50 (m, 1H), 3.73 (dt, J = 9.6, 6.8 Hz, 1H), 3.85 (m, 13 1H), 4.60 (m, 1H), 5.33–5.52 (m, 2H). C NMR (100.5 MHz, CDCl3) δ 13.9, 19.5, 22.3, 25.4, 27.0, + 27.9, 30.6, 31.7, 62.2, 67.0, 98.6, 125.4, 131.9. HRMS–ESI (m/z): [M+Na] calcd for C13H24O2Na, 235.16685; found, 235.16661. (Z)-N,N-Dibenzyl-2-hepten-1-amine (2d) Bn2N C4H9 H H 2d The product 2d was purified by flash chromatography on silica gel (0–5% EtOAc/hexane) (77% isolated yield from 1d, Z/E 87:13). 2d was consistent with the the literature data.11 (Z)-1-Methoxy-2-(1-propen-1-yl)benzene (2e)10 S3 Me MeO H H 2e The product 2e was purified by flash chromatography on silica gel (0–5% EtOAc/hexane) (60% 1 isolated yield from 1d, Z/E 97:3). Colorless Oil. H NMR (400MHz, CDCl3) δ 1.83 (dd, J = 7.6, 1.6 Hz, 3H), 3.84 (s, 3H), 5.84 (dq, J = 11.6, 7.6 Hz, 1H), 6.54 (dd, J = 11.6, 1.6 Hz, 1H), 6.87–6.96 13 (m, 2H), 7.19–7.28 (m, 2H). C NMR (100.5 MHz, CDCl3) δ 14.6, 55.4, 110.3, 119.9, 125.2, 126.2, 127.9, 130.1, 156.9. (Z)-1-Methoxy-4-(1-propen-1-yl)benzene (2f)12 MeO Me H H 2f The product 2f was purified by flash chromatography on silica gel (0–5% EtOAc/hexane) (58% 1 isolated yield from 1e, Z/E 95:5). Colorless Oil. H NMR (400MHz, CDCl3) δ 1.89 (dd, J = 7.2, 2.0 Hz, 3H), 3.83 (s, 3H), 5.70 (dq, J = 11.6, 7.2 Hz, 1H), 6.37 (dd, J = 11.6, 2.0 Hz, 1H), 6.85–6.90 (m, 13 2H), 7.22–7.29 (m, 2H). C NMR (100.5 MHz, CDCl3) δ 14.6, 55.2, 113.5, 125.1, 129.2, 130.0, 130.3, 158.1. (Z)-1,3-Dimethoxy-2-(1-propen-1-yl)benzene (2g) OMe Me MeO H H 2g The product 2g was purified by flash chromatography on silica gel (0–10% EtOAc/hexane) (36% 1 isolated yield from 1g, Z/E >99:1). H NMR (400MHz, CDCl3) δ 1.58 (dd, J = 7.2, 2.0 Hz, 3H), 3.83 (s, 6H), 5.95 (dq, J = 11.2, 7.2 Hz, 1H), 6.24 (dd, J = 11.2, 2.0 Hz, 1H), 6.58 (d, J = 8.4 Hz, 13 2H), 7.21 (t, J = 8.4 Hz, 1H). C NMR (100.5 MHz, CDCl3) δ 15.5, 55.6, 103.6, 114.7, 121.0, + 128.1, 129.3, 157.7. HRMS–EI (m/z): [M] calcd for C11H14O2, 178.09938; found, 178.09889. (Z)-Methyl 4-(1-Decen-1-yl)benzoate (2h) O MeO C8H17 H H 2h The product 2h was purified by flash chromatography on silica gel (0–10% EtOAc/hexane) (66% 1 isolated yield from 1f, Z/E 93:7).