INTRAMOLECULAR NITRILIMINE CYCLOADDITIONS TO THE THIOPHENE AND THE FURAN RINGS

摘要

The dipolarophilic behaviour of furan and thiophene rings have been exploited in the intramolecular cycloadditions of nitrilimines.These labile intermediates were generated from the corresponding hydrazonoyl chlorides by treatment with silver carbonate.The extent of formation of tricyclic cycloadducts was strongly dependent on the substitution pattern of the heteroaromatic ring, thus reflecting the HOMO-dipole controlled nature of the cycloaddition.