Synthesis of (E)-α-hydroxyethyl-α,β-unsaturated aldehydes by the reaction of tetrahydrofuran and aromatic aldehydes

Abstract

Although α-functionalized α,β-unsaturated aldehydes have important applications in biomedicine, there are few reports on their synthesis. In this article, a new domino reaction for the synthesis of (E)-α-hydroxyethyl-α,β-unsaturated aldehydes was introduced, in which tetrahydrofuran (THF) used as carbonyl block. The first step is an oxidation of THF to 2-hydroxytetrahydrofuran (HTHF) and then it was condensed with ethanolamine under acid catalysis to obtain imine intermediate, which was further isomerized to enamines and used as nucleophiles to attack aldehydes. This is a simple and efficient way for the preparation of (E)-α-hydroxyethyl-α,β-unsaturated aldehydes with notable advantages of a simple procedure, widespread availability of the substrates.