Nitrogen heterocycles have aroused considerable interest due to their presence in a number of therapeutically and biologically active compounds.'Compared to the remarkable development of catalysis to provide carbocyclic compounds in an optically active f~ rm,~,~ only a few methods have been reported for catalytic asymmetric synthesis of heter~ cycles.~ Recently, it has been reported by Saegusa and co-workers that 2-buten-1, 4-ylene ...
