Rhodium-catalyzed synthesis of γ-butyrolactams and pyrrolidines via cycloisomerization of N-tethered 1,6-enynes

A rhodium-catalyzed cycloisomerization reaction of N-tethered 1,6-enynes with an intramolecular halogen shift has been developed, providing a useful process for the synthesis of stereo defined gamma-butyrolactam and pyrrolidine derivatives in good to excellent yields. Effects of both electronic feature and steric structure of the substrates on the outcome of the reaction were investigated. (C) 2010 Elsevier Ltd. All rights reserved.