TRANSITION-METAL CATALYZED RADICAL CYCLIZATION - NEW PREPARATIVE ROUTE TO GAMMA-LACTAMS FROM ALLYLIC ALCOHOLS VIA THE [3.3]-SIGMATROPIC REARRANGEMENT OF ALLYLIC TRICHLOROACETIMIDATES AND THE SUBSEQUENT RUTHENIUM-CATALYZED CYCLIZATION OF N-ALLYLTRICHLOROACETAMIDES

A sequence of reactions including [3.3]-sigmatropic rearrangement of allyl trichloroacetimidates (Overman rearrangement) followed by ruthenium-catalyzed cyclization of N-allyltrichloroacetamides provided a novel method for preparing trichlorinated gamma-lactams from allylic alcohols. No delta-lactam was formed as a byproduct. The cyclization of secondary N-allyltrichloroacetamides proceeded with good diastereoselectivity. Two types of tandem cyclizations to form bicyclic lactams took place in the cyclization of N-allyltrichloroacetamides from geraniol and linalool.