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Chemical Synthesis and Self-Assembly of a Ladderane

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Chemical Synthesis and Self-Assembly of a Ladderane Chemical Synthesis and Self-Assembly of a Ladderane Phospholipidf! Mercer, J. A. M.; Cohen, C. M.; Shuken, S. R.; Wagner, A. M.; Smith, M. W.; Moss, F. R.; Smith, M.D.;! Vahala, R.; Gonzalez-Martinez, A.; Boxer, S.G.; Burns, N. Z. J. Am. Chem. Soc. 2016, 138, 15854. O H H H H H O O Me N+ 3 O P O H H H H O- O H H H H H H H ! Michael Houghton Wipf Group 12/24/16 1 Michael Houghton@ Wipf Group Page 1 of 12 12/25/2016 General Uses and Types of Lipids - Lipids are used to provide and store energy, absorb vitamins, cell membrane and general cell health, signaling, and numerous other biological activities. OH H H H H H H H HO O Cholesterol Testosterone O HO Linoleic acid O O O O O O Triglceride (coconut oil) HO O Elaidic acid 2 Michael Houghton@ Wipf Group Page 2 of 12 12/25/2016 Ladderane Phospholipid is Found in Anammox Bacteria - Anammox- Anaerobic Ammonium Oxidizing - These bacteria convert ammonia and nitrite into dinitrogen and water - This process takes place in a unique organelle, the anammoxosome, which is composed of ~ 90 % ladderane phospholipds. - These densely packed phospholipds are believed to keep hydrazine and hydroxylamine waste products from damaging the rest of the cell. - There are five types of known anammox bacteria: Brocadia, Keunenia, Anammoxoglobus, Jettenia and Scalindua. - Anammox bacteria are used industrially to purify ammonia rich, contaminated water. - Purification difficulties have prohibited the isolation of pure material and useful quantities of material. 3 Michael1. Reimann Houghton@, J.; Jetten Wipf, M. GroupS.; Keltjens, Jan T. Metal Ions in Life Sciences.Page 3 15of .12 Springer. 257-313. 2. Strous, M. et al. Nature. 1999, 400, 12/25/2016446-449. 3. Kartal, B.; Keunen, J. G.; Van Loosdrecht, M. C. Science. 2010, 328, 702-703. Previous Synthetic Efforts – Racemic “The recent report of the remarkable pentacyclic C20-fatty acid methyl ester from the anammoxic microbe Candidatus Brocadia anammoxidans opens a fascinating new chaper in the field of natural products.” - E. J. Corey Cbz 1. H , PtO , NaNO , 1. hv, 2-cyclopenten-1-one, 2 2 2 NCbz N N o o CbzN EtOH/THF, 23 C CbzN MeCN, 23 C (40 % b.s.m.) N 2. Zn, AcOH, 95 oC 1. H , Pd–C, EtOH, 23 oC Br 2 O (80 %, 2 steps) then O , 23 oC (76 %) Br 2 1. HC(OMe)3, PTSA 1. HCO2Et, PhH, MeONa, 1.hv, MeOH, Et3N, MeOH, 40 oC (91 %) 23 oC 23 oC (72 %) o O O 1. hv, MeCN, 50 C 1. TsN3, Et3N, CH2Cl2 o o then AcOH/H2O, 23 C 23 C (80 %, 2 steps) (6 %) N2 1.LDA, (Br,Ph3P(CH2)6CO2H) THF, –78 to 23 oC (67 %) O 2. NH2NH2, CuSO4, O2, CHO o OMe EtOH/H2O, 23 C (88 %) o 3. CH2N2, Et2O, 0 C (95 %) 4 MichaelMascitti ,Houghton@ V., E. J. Corey. Wipf JACS Group, 2004, 126, 15664-15665. Page 4 of 12 12/25/2016 Previous Synthetic Efforts – Enantioselective O 1. NaHMDS, HCO2Et, 1.hv, MeOH, Et3N, hv, MeCN THF, –30 oC to 0 oC 23 oC O O + –15 oC (78 %) 1. TsN3, Et3N, CH2Cl2 2. LiOH, H2O/THF, o o 23 C (62 %, 2 steps) N2 23 C (86 %, 2 steps) O 1.(COCl)2, DMF, 1.hv, 1.NaHMDS, THF, –78 oC DMF, 23 oC o SiPhMe2 then TMSCl, –78 to 0 C BrCCl , o CO H 2. 3 MeCN, 23 C (50 %) O 2.NBS, THF, –50 to –30 0C 2 N S DMAP, 75 oC, 3. TBAF, THF, 23 oC ONa 15 min; (53 %, 3 steps) hv, 10 oC, 10 min (79 %) Me2PhSi 3. t-BuOK, DMSO 50 oC (84 %) NaHTe, EtOH, 23 oC O O 79 % O OMe O O O O (PhMe2Si)2Cu/ (CF CO) O (CN)Li2 HF (aq) 3 2 o o o TBSO THF, –50 to 0 C TBSO MeCN, 23 C HO C5H5N, –20 C SiPhMe2 71 % SiPhMe2 80 % SiPhMe2 DBU 86 % 5 MichaelMascitti ,Houghton@ V., E. J. Corey. Wipf JACS Group, 2006, 128, 3118-3119. Page 5 of 12 12/25/2016 Retrosynthetic Analysis O H H H H H O O Me N+ 3 O P O H H H H O- O H H H H H H H Natural Ladderane Phospholipid O H H H H H H H H H H H HO + H H H H H H H H H H [5]-ladderanoic acid O O HO H H H H H H H H x x + H H H H H H H O O [3]-ladderanol 6 Michael Houghton@ Wipf Group Page 6 of 12 12/25/2016 Route to [5]-Ladderanoic Acid Cl H H H H H H H HO 1. MsCl (94 %) KOt-Bu CuOTf O S HO 2. Na2S DMSO hv = 254 nm (49 %) H o H H H H H H2O2 (93 %) H PhH, –4 C > 10 g 3. SO2Cl2 (89 %) (42 %) Confirmed by X-ray 7 Michael Houghton@ Wipf Group Page 7 of 12 12/25/2016 Route to [5]-Ladderanoic Acid 1. OTBS Cu(MeCN)4PF6 Li (R)-DM-SEGPHOS 1. Mn(TMP)Cl H H H H H H H H H 6 NaOCl (40 %) B2pin2, NaOt-Bu Bpin NBS, NaOMe 2. KOt-Bu (95 %, 90 % ee) 2. HF-pyr (91 %) KOt -B H H H H H H H H (88 %, 2 steps) H H H H H H 1. H , Ra-Ni HO H H H H HO 2 O 2. CrO3/H2SO4 H H H H (86 %, 2 steps) H H H H > 600 mg synthesized 8 Michael Houghton@ Wipf Group Page 8 of 12 12/25/2016 Route to [3]-Ladderanol OH O O hv = 350 nm H H H Br Br o Br 1. CrO3, H2SO4 0 C pyridine Br (82 %) Br (82 %) Br (73 %, 2 steps) H H H H OH O O H O O H H H OPMB H H H ZnI 8 PMBO 8 Br (78 %) H H H H H H O O 9 Michael Houghton@ Wipf Group Page 9 of 12 12/25/2016 Route to [3]-Ladderanol NH2 O N H H H H H H NH2NH2 PMBO 8 PMBO 8 (78 %) H H H H H H O N H2N H H H 1. Crabtree's H H H HO Cu - TMEDA PMBO 8 cat., H2 (99 %) 2. DDQ (89 %) H H H H H H (78 %, 2 steps) > 600 mg synthesized 10 Michael Houghton@ Wipf Group Page 10 of 12 12/25/2016 Final Route to Ladderane Phosopholipid NaH/DMF, then PMBO OTr [3]-ladderanol-OMs H H H HCl PMBO OTr O OH (60 %) CH2Cl2/MeOH (86 %) H H H O H H H H H O PMBO OH EDC, HOBt H H H [5]-ladderanoic acid DDQ O PMBO H H H H H H H i-PrNEt2, DMF O H CH2Cl2/H2O (74 %) (89 %) H H H H H H O O H H H H H 1. O H H H H H O P Cl O O O + O Me3N HO H H H H Me3N O P O H H H H O H H H H O- O H H H H 2. Me3N, MeCN 75 oC H H H (50 %, 2 steps) H H H 11 Michael Houghton@ Wipf Group Page 11 of 12 12/25/2016 Conclusions § Successfully completed first enantioselective selective synthesis of a complete ladderane phospholipid § Provided first proof of absolute configuration of natural ladderane. § Developed novel dimerization of bicyclohex[2.2.0]ene to form the fused pentacyclobutane core. § Confirmed Wipf et al computations on sign of Trans-(R)-ladderane 12 MichaelZuber, G.; Houghton@ M.-R.; Beratan Wipf, GroupD. N.; Wipf, P. Chirality 2005, 17, 507-510.Page 12 of 12 12/25/2016.
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