An efficient route to the pyrrolizidine ring system via an N-acyl anion cyclisation process

Article abstract of DOI:10.1016/0040-4020(96)00049-X

An enantioselective route to the pyrrolizidine ring system has been developed which uses an N-acyl anion cyclisation reaction as the key step. This methodology has provided the natural pyrrolizidines (-)-(1R, 8S)-1-hydroxy-pyrrolizidine 7, (-)-pyrrolizidin-1-ene-3-one 9 and (±)-trachelanthamidine 14. Extension of the process to an N-propionyl substrate provides ready access to a series of 2-methyl pyrrolizidines.