Benzophenones selectively attack the γ unsubstituted terminus of gem-dichloroallyl lithium, but show an increasing opposite selectivity for the α terminus in the presence of 12-crown-4 and cryptand [2.1.1]. The products coming from the α addition reaction undergo epoxidation by internal Sn reaction at −95 °C. Ab initio theoretical computations on the corresponding transition structures are also reported
二苯甲酮选择性地攻击宝石-二
氯烯
丙基锂的γ未取代末端,但在12-crown-4和穴状
配体的存在下,对α末端显示出越来越高的相反选择性[2.1.1]。来自α加成反应的产物在-95°C下通过内部S n反应进行环氧化。从头开始对相应的过渡结构进行理论计算,并进行了讨论。