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

Abstract

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.

Keywords

• calixpyrroles
• diastereoselective synthesis
• organocatalysis
• aldol addition
• 2-Trimethyl-silyloxyfuran