D. A. Evans. M. Calter The Aza-Cope Rearrangement Chem 115 N-Acyliminium lon Rearrangements: Hart JOC 1985, 50, 235 N-Acyliminium lon Rearrangements Synthesis of (-)-hastanecine: Hart JOC 1985, 50, 235 erved an unusual product while trapping mediates of N-acyliminium olefin 1)MeC(OEt)3. CF3CO2s TF Et3 SiH, Me' well-precedented reaction, 74%6 yield C3H, HCO2H NaBH4 C3H7 Expected product of nexpected, must be product iminium salt reduction. of 2-aza-Cope, followed by 3 and 4 substitution favors the rearrangement H2O,89% 1)BU3SnH 85%H0 astancine 2 is the sole product in 91% yield 32B-1011/24/9310:26AMN-Acyliminium Ion Rearrangements Synthesis of (-)-hastanecine: Hart JOC 1985, 50, 235. 1)MeC(OEt)3, H+, 145oC 2)OH- 3)SO2Cl 4)Curtius 5)TFA 52% + 81% NaBH4, MeOH, 83% + HCO2H + MeOH, H2O, 89% overall 1)H2, Pd/C 2)AcCl 90% HgO,I2 85% 1)Bu3SnH 2)LiAlH4 82% (-)-hastancine 2 is the sole product in 91% yield. N-Acyliminium Ion Rearrangements: Hart JOC 1985, 50, 235. Hart observed an unusual product while trapping the intermediates of N-acyliminium olefin cyclizations. TFA + No Et3SiH, normal, well-precedented reaction, 74% yield Et3SiH, 73% Expected product of iminium salt reduction. 3 : 5 + Unexpected, must be product of 2-aza-Cope, followed by reduction. 3 and 4 substitution favors the rearrangement. HCO2H + 3 4 cycln. + + 2-aza-Cope 1 2 D. A. Evans, M. Calter The Aza-Cope Rearrangement Chem 115 N OH O C3H7 C3H7 O N N O C3H7 CF3CO2 N O C3H7 C3H7 O N Me O N N O H O Me Me O Me N O A N O Me O Me Me HCO2 N Me Me Me Me OBn BnO Me OH NH2 O O O AcO N O O BnO OAc OAc BnO OH O N N OAc OBn O OAc O OBn N N OAc O Me Me HCO2 HO Me Me O OH N N OAc O Me Me HO N I O OAc N OH BnO BnO AcO AcO HO 32B-10 11/24/93 10:26 AM