酸碱催化下1,2-环氧化合物开环反应的区域选择性初探

A Study on the Regioselectivity of Ring-opening Reaction of 1,2-Epoxides Catalyzed by Acids or Bases

探讨酸碱催化下1,2-环氧开环反应区域选择性,结果表明:对烷基取代的环氧乙烷而言,酸或碱催化,亲核试剂一般进攻环氧化合物位阻较小的1-位碳原子,但是芳基取代的环氧乙烷(如苯基环氧乙烷),亲核性一般的亲核试剂进攻环氧化合物的2-位碳原子,亲核性特别强的亲核试剂,进攻环氧化合物的1-位碳原子。纠正部分教科书中对于1,2-环氧开环反应的区域选择性不全面解释。

The regioselectivity of the opemng-reacuon of 1,2epoxides was investigated, catalyzed by acids or bases. For the alkyl epoxyethane, nucleophiles attack the less hindered 1 carbon atoms of epoxides. For aryl epoxyethane （i.e. styrene oxide）, the normal nucleophiles attack the bulky 2 carbon atoms of epoxides, but the strong philphers attack the less hindered 1carbon atom of epoxide. This research corrects the explanation on the regloselectivity of opening-reaction of 1,2 epoxides in some books.