Metal-Mediated Reactions of α-Bromomethyl-Propenoate Esters

Abstract Methyl 2-bromomethylprop-2-enoate reacts with benzaldehyde and with salicylaldehyde via its Sn and Zn complexes under aqueous conditions to form α-methylene-γ-lactones in high yields. In the case of salicylaldehyde X-ray analysis proves conclusively formation of a five- rather than a seven-membered ring. Under the above conditions 2-bromomethyl-3-phenylprop-2-enoate does not afford any cyclic products.