D. A. Evans. M. Calter The Aza-Cope Rearrangement Chem 115 tabersonine: Overman JOC 1983, 48, 2685 ()-Crinine: Overman Helv. Chim. Acta 1985, 68, 745 COgMe OTMS ZnBr2 1: 1 mixture of diastereomers 45% yield of( 1R, 2R)after (1s,2S) 0c 6hr,90% AgNO3. 80% rality due to ring filips, so product with R=Bn give the same result (*] -16-methoxytabersonine 21% overall 32B-0711/24/9310:01AMD. A. Evans, M. Calter The Aza-Cope Rearrangement Chem 115 (±)-16-methoxytabersonine 1)LDA 2)MeOCOCl 31% 110oC, 6 hr, 90% 1)Ph3P=CH2, 2)40% KOH, 93% 80% + 1)MCPBA 2)CaCO3, 44% 1)NaI 2)NH3 3)MeOCOCl, 68% ZnBr2, 84% + (±)-16-methoxytabersonine: Overman JOC 1983, 48, 2685. This iminium-enol intermediate undergoes the intermolecular Mannich reaction before losing chirality due to ring flips, so product is enantiomerically pure. Experiments with R=Bn give the same results. 5 steps, 21% overall Pd/C, Cyclohexene, 80% + + 2-aza-Cope Mannich AgNO3, 80% 91% + Swern, 95% HCHO, KCN92% 1:1 mixture of diastereomers, 45% yield of (1R,2R) after seperation (1R,2R) (1S,2S) + + (-)-Crinine: Overman Helv. Chim. Acta 1985, 68, 745. OTMS Et SPh SPh Cl Cl O Et Cl N CO2Me Et N SPh CO2Me Et O H OMe NBOC Li TMSO CN Li N Et O O O NHBOC OMe OMe NH2 HO O Et HN N Et N Et N MeO NH2 MeO MeO N Et N CO2Me H O N Me Ph Me2Al H OH NH Me Ph NH Me Ph OH N Me Ph OH CN O O N CN O Me Ph N Me Ph CN HO Li O O N OH Ar R N R Ar H OH Ar N Bn O H N H O O O O O HO H N 32B-07 11/24/93 10:01 AM