Reaction of the 1,2-bisketene (Me(3)SiC=C=O)(2) (1) with alcohols (ROH) catalyzed by LiOR gives rapid and efficient conversion to mixtures of the meso and dl succinates (Me(3)SiCHCO(2)R)(2) (4). There is a change in selectivity with the dl/meso ratio varying from 18/82 with MeOH to 92/8 for t-BuOH. This procedure occurs with minimal desilylation, which is the predominant path in the uncatalyzed reaction
1,2-双烯酮(Me(3)SiC = C = O)(2)(1)与LiOR催化的醇(ROH)的反应可快速有效地转化为内消旋和dl
琥珀酸酯的混合物(Me(3 )SiCHCO(2)R)(2)(4)。选择性发生变化,dl /内消旋比从MeOH的18/82变为t-BuOH的92/8。该过程以最小的甲
硅烷基化作用进行,这是未催化反应的主要途径。提出
锂的醇盐对由烯丙基氧与烯基氧的配位作用诱导的烯酮的羰基碳的优先进攻,以解释低甲
硅烷基化程度。内消旋和dl构型的立体
化学分配是基于混合
琥珀酸酯和(13)C,(1)H卫星光谱的邻位H,H偶合常数,并通过X射线结构测定得到证实。