Calixpyrrole Derivatives: Multi Hydrogen Bond Catalysts for γ-Butenolide Synthesis

摘要

Calix[4]pyrrole (>1)>, calix[2]m-benzo[4]pyrrole (>2), 10α,20β- and 10α,20α- bis(4-nitrophenyl)-calix[4]pyrroles >3 and >4, respectively>, were found to exhibit various organocatalytic activities in the diastereoselective vinylogous addition reaction of 2-trimethylsilyloxyfuran (TMSOF, >7) to aldehydes. The γ-hydroxybutenolide products are obtained in fairly good yields and with moderate diastereoselectivity. The structures of the catalysts, as well as the reaction conditions, strongly influence the efficiency of the reaction.