Theoretical Studies on the Mechanism of the Michael Addition Reaction Catalyzed by a Thiourea‐Cinchona‐Amine: Triple Activation

Abstract

This paper attempts to illuminate the mechanism of the catalytic Michael addition of 2,4-pentanedione with acrylaldehyde mediated by at hiourea-cinchona-amine catalyst via density functional theory calculations. The calculated results show that the CÀCc oupling easily occurs once the electronegative and electropositive sites of the reactants are generated by the catalyst. However,t he previously proposed mechanism with the formation of an imine from the carbonyl group of reactants and the amine group of catalyst fails due to high reactionb arriers for both the formation of the imine and the hydrolysis of the imine with water in order to regeneratet he catalyst. Instead,t he reactionp athways going throught he protonation of the amine in the catalyst and formationo fh ydrogen bonds betweent he reactants and catalyst have smaller barriers. Our study will be helpful in designing new catalysts or extending the substrate scope of the reaction.

Theoretical Studies on Electrophilic Aromatic Substitution Reaction for 8-Hydroxyquinoline

“…Theoretical studies are valuable approaches to explore the mechanism of reactions in the molecules and their electronic structures levels in addition to electronic parameters that acquired by means of theoretical calculations employ the computational methods of quantum chemistry 1,2 . The improvement in theoretical studies and applications have accomplish a point where predicted features of logical accuracy can be obtained from DFT (density functional theory) studies 3,4 .…”