D.A. Evans. D. Barnes Carbene heteroatom transformations Ylid formation Chem 206 Ylid Formation versus Cyclopropanation Tandem O-H Insertion/Claisen Rearrangement EO2C、 Rh2oAc)e Me phh,△,20mn OCH catalyst Temp(C) Pd2CL2(C3H 53 COmE fast (PhCoCHCOMe)2 80 50 13 (MeO)3PCul RT Z-Eno transition state Jood JACS 1997 9641 Rh2(oAc Wood,JAcs199,121,1748 enantiomer is it is evident that these are reactions of metal carbenoids Bien. s: Gillon. A: Kohen. s. J. Chem. Soc. Perkin trans/ 1976. 489-492 PhH△,18hs|Ho 00 0 L CH2+-Bu E-Eno Transition state 479 CO2Et Merck Thienamycin Process PhH,80°C transfer hienamycin Doyle, M P, et al. J. Org. Chem. 1991, 56, 820-829 Doyle, M. P Taunton, J; Pho, H.Q. Tetr 1989,30,5397 Salzmann, JAcs 1980 6161Chem 206 Ylid Formation versus Cyclopropanation D. A. Evans, D. Barnes 3 13 35 58 54 53 50 3 1 15 RT 80 RT RT 80 Pd2Cl2 (C3H5 )2 Cu(PhCOCHCOMe)2 (MeO)3PCuI Rh2 (OAc)4 None catalyst Temp (°C) %1 %2 2 1 catalyst Bien, S.; Gillon, A.; Kohen, S. J. Chem. Soc. Perkin Trans. I. 1976, 489-492 EtO CHN2 O O EtO O O MLn O EtO2C O EtO O O O EtO O O OEt it is evident that these are reactions of metal carbenoids Rh2 (pfb)4 PhH, reflux - + insertion products H transfer Doyle, M. P., et al. J. Org. Chem. 1991, 56, 820-829. Doyle, M. P.; Taunton, J.; Pho, H. Q. Tetrahedron Lett. 1989, 30, 5397. pfb = perfluorobutyrate Me N t-Bu O O N2 CO2Et O N O Me O EtO O N O Me O EtO CH2 t-Bu CH2 t-Bu L4Rh2 O N O Me OH EtO CH2 t-Bu + Carbene Heteroatom Transformations: Ylid Formation Tandem O-H Insertion/Claisen Rearrangement Me OMe O N2 O Me OH + Me OCH3 HO O O Me Wood, JACS 1997 9641 98% ee 95% ee O O X Me CO2Me Me [3,3] O O X Me CO2Me Me slow fast (66%) Wood, JACS 1999, 121, 1748 Me OCH3 HO O O Me Me OMe O O O Me PhH, D, 20 min O Me HO CO2Me Me PhH, D, 18 hrs Z-Enol Transition State E-Enol Transition State 47% ee (75%) The opposite enantiomer is observed! Merck Thienamycin Process NH H Me OH H N2 O O O NO2 O Rh2 (oct)4 N H Me OH H O OH CO2p-NB PhH, 80 °C 100% N H OH H O S CO2 NH3 Salzmann, JACS 1980 6161 Thienamycin X = H, Rh(II) ?? H H + Rh2 (OAc)4