[摘要]：A review. The torquoselectivity-controlled olefination of carbonyl compds. with ynolates affording tetrasubstituted alkenes is described. The E/Z selectivity is detd. in the step consisting of electrocyclic ring opening of the b-lactone enolates (oxetenes) derived from cycloaddn. of ynolates with carbonyl compds. Theor. calcns. revealed that several secondary orbital interactions are crit. for the high torquoselectivity. This methodol. is a novel olefination for constructing multisubstituted olefins.
