Lewis acid catalysis of the ene addition of dimethyl oxomalonate and butyl glyoxylate to olefins: Formation of cyclic ethers and lactones

Abstract

The Lewis acid (SnCl4, TiCl4) catalyzed ene addition of dimethyl oxomalonate and butyl glyoxylate to pent-1-ene and 3-methylbut-1-ene has been investigated. Side reactions have been noted leading variously to the formation of δ-lactones and/or cyclic esters (tetrahydrofurans). The effect on the reaction course of the structure of the substrates has been discussed.