Lithium carbenoids induced ring enlargement of silacyclobutane into 2-halo-1-silacyclopentane and its use in organic synthesis

Abstract

An addition of lithium diisopropylamide to a solution of 1,1-dimethyl-1-silacyclobutane and dihalomethane such as CH2I2, CH2Br2, or CH2Cl2 provided the corresponding 1,1-dimethyl-2-halo-1-silacyclopentane in good yield. The reactions of 1,1,2-trimethyl-1-silacyclobutane or 1,1,3-trimethyl-1-silacyclobutane with lithium carbenoids are also described. Treatment of 2-iodo-1-silacyclopentane with tert-butyllithium gave 2-lithio-1-silacyclopentane which reacted with electrophiles to afford the corresponding adducts. © 1993.