Synthesis of γ-hydroxy-γ-perfluoroalkyl butenolides and exocyclic double bond butanolides via regioselective allylic alkylations of MBH carbonates with 2-perfluoroalkyl-oxazol-5(2H)-ones

Abstract

Herein, two general one-pot two-step methods for the preparation of γ-hydroxyl-γ-perfluoromethyl butenolides and γ-hydroxyl-γ-perfluoromethyl exocyclic double bond butanolides from Morita–Baylis–Hillman (MBH) carbonates with 2-perfluoroalkyl-oxazol-5(2H)-ones have been reported for the first time. These two methods exploited the regiodivergent synthesis of α-selective or γ-selective allylic alkylation products by employing TMG or DABCO as the catalyst, respectively. After hydrolysis and cyclization, two series of γ-perfluoromethyl-hemiketals could be obtained with wide substrate scope under mild reaction conditions. In addition, we have preliminarily realized the enantioselective regiodivergent synthesis of α-selective allylic alkylation (60% yield, 34% ee) and γ-selective allylic alkylation products (up to 95% yield, 99% ee and >20 : 1 dr) using bifunctional chiral phosphine-ester/amide thiourea as the catalyst, respectively.