Stable organozinc compounds derived from alkyl 3-alkyl 2-(bromomethyl) propenoates reacted with ketones and aldehydes to give alpha-methylene gamma-butyrolactones in excellent yields. Different reaction parameters were studied and some transition states were proposed.
Drewes, S. E.; Hoole, R. F. A., Synthetic Communications, 1985, vol. 15, # 12, p. 1067 - 1074