Synthesis of 3-aminopyrrolidines and piperidines from endocyclic enamine derivatives

Reactions of endocyclic enecarbamates to form functionalized 3-aminopyrroli dines and piperidines are described. Iodoamination or N-acyl-2-pyrrolines f ollowed by aziridination in methanol is an effective route to N-acyl-3-amin o-2-methoxypyrrolidines. Azidomethoxylation of endocyclic carbamates by cer ic ammonium nitrate (CAN) in the presence of NaN3 and methanol gives 3-azid o-2-methoxypiperidines and pyrrolidines. Formation and trapping of the N-ac yliminium ions derived from these substrates under Lewis acidic conditions was also explored for the stereoselective preparation of 2-alkyl pyrrolidin e and piperidine derivatives. (C) 2001 Published by Elsevier Science Ltd.