Simmons‐Smith reaction of allylic hydroxylated long chain α, β‐unsaturated esters

The reaction of methyl 4‐hydroxy‐ trans ‐2‐hexadecenoate [1 b ] with diiodomethane in the presence of zinc‐copper couple yielded methyl 4‐methoxy‐ trans ‐2,3‐methylenehexadecanoate [2] in a 70% yield, together with methyl 4‐hydroxy‐ trans ‐2,3‐methylenehexadecanoate [3] (∼20%). The presence of an allylic hydroxyl group in the α,β‐unsaturated ester increases the yield of the cyclopropanation product. The formation of o ‐methyl ether reveals the dual role of cyclopropanation and etherification by S.S. reagent of a hydroxylated olefinic compound.