An expedient stereoselective synthesis of (E)-α,β-unsaturatedesters and thioesters using FeCl3•6H2O

Facile and convenient synthesis of a,alpha,beta-unsaturated esters and thioesters from alkylidene derivatives of Meldrum's Acid is described. This method uses catalytic amount of FeCl3.6H(2)O (0.001-0.005 equiv) with alcohols/thiols (1 equiv) in dry CH3NO2 followed by catalytic amount of piperidine. A variety of a, alpha,beta-unsaturated esters and thioesters have been synthesized with high E-stereoselectivity in good to excellent yields. The application of this methodology is demonstrated by gram scale synthesis of octinoxate, a sunscreen agent, and other p-methoxycinnamate esters. (C) 2017 Elsevier Ltd. All rights reserved.