Diastereoselective Synthesis of Medium-Sized Lactones by Cu(bpy)CI Catalyzed Cyclization of Trichloroacetates

Abstract

Six alkenyl trichloroacetates were heated in 1,2-dichloroethane as solvent in the presence of 30% of the Cu(I)C1/2,2′-bipyridine complex as catalyst at temperatures between reflux and 190 °C (sealed tube) to effect cyclization via a chlorine transfer process providing 8- and 9-membered lactones in moderate to good yields.