Smith Amos B, Pitram Suresh M, Gaunt Matthew J, Kozmin Sergey A
Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia Pennsylvania 19104, USA.
J Am Chem Soc. 2002 Dec 11;124(49):14516-7. doi: 10.1021/ja0283100.
High chemoselectivity can be achieved in the addition of lithium dithiane anions to vinyl epoxides exploiting the steric nature of the dithiane substituent. Unencumbered dithiane anions afford SN2 adducts, whereas sterically encumbered anions lead primarily to SN2' adducts. Furthermore, the SN2' addition occurs syn to the vinyl epoxide.
利用二硫烷取代基的空间性质，在二硫烷锂阴离子与乙烯基环氧化物的加成反应中可实现高化学选择性。未受阻碍的二硫烷阴离子生成SN2加合物，而空间位阻较大的阴离子主要生成SN2'加合物。此外，SN2'加成反应是与乙烯基环氧化物顺式进行的。
