tetraphenylstibonium bromide, similarly promoted the selective addition of tin enolates to the carbonyl moiety in α-halo ketones. The reaction with 2-chlorocyclohexanones and the enolates gave chlorohydrins bearing chloro- and hydroxyl groups in the cis-conformation. Chemoselective carbonyl addition to acyclic α-halo ketones was followed by effective cyclization to 2-(2-oxoethyl)oxiranes. The structural and bonding
两种类型的催化剂,五配位
有机锡溴化物和
四苯基溴化锑,同样促进了烯醇
锡选择性加成到 α-卤代酮的羰基部分。与
2-氯环己酮和烯醇化物的反应得到带有顺式构象的
氯和羟基的
氯代醇。
化学选择性羰基加成到无环 α-卤代酮,然后有效环化成 2-(2-氧乙基)
环氧乙烷。两种催化剂的结构和键合类比可能是导致
化学和立体选择性加成的相似催化活性的原因。