(+)-R-(4-methylphenyl)sulphoxides were lithiated and alkylated with lithium α-bromomethyl acrylate with medium to high diastereoselection; condensation products gave in two steps optically pure α-methylene-γ-lactones.
将光学纯的(+)-R-(4-甲基苯基)亚砜
锂化,并用中等至高非对映选择性的
丙烯酸α-
溴代
甲基丙烯酸锂烷基化;缩合产物分两步得到光学纯的α-亚甲基-γ-内酯。