The reaction of 1,3,2-dioxastannolans with diacyl chlorides: decarbonylation in the reaction with oxalyl chloride

Abstract

Abstract 2,2-Dibutyl-1,3,2-dioxastannolans react with carbonyl chloride to give the corresponding ethylene carbonates, and with malonyl chloride or succinyl chloride to give the oligomeric malonates or succinates. The reaction of oxalyl chloride, however, depends of the number of methyl substituents carried by the carbon atoms of the ring; with none, ethylene oxalate is essentially the only product, but increasing methylation induces the evolution of carbon monoxide and the formation of the ethylene carbonate until, with four methyl substituents, only the carbonate of pinacol, and no oxalate is formed, providing a striking example of the Thorpe-Ingold effect. The mechanism of this decarbonylation is discussed.