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 γ-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.