Intramolecular 1,4-addition of nitrogen nucleophile and bromine electrophile to conjugated 1,3-enyne

We have discovered a series of N-bromosuccinimide-promoted 1,4-bromocyclization reactions for conjugated 1,3-enynes. Various nitrogen nucleophiles could be added to conjugated enynes to generate bromoallenyl substituted nitrogen heterocycles. These processes led to simultaneous formation of a highly functionalized axially chiral allene and a stereogenic center under mild conditions. (C) 2011 Elsevier Ltd. All rights reserved.