The reaction of a monochlorocarbenoid with some methoxycycloalkenes—an observation on the mechanism of the insertion reaction of carbenes and carbenoids into double bonds

Abstract

The products from the reaction of the monochlorocarbenoid, derived from butyl lithium and dichloromethane, on 3- and 4-methoxycyclohexene and 3- and 4-methoxycyclopentene were examined. The major products have the chlorocyclopropane ring syn to the OMe group. In the products from the 4-methoxycycloalkenes the major syn product has the chloro group exo, the 3-methoxycycloalkenes are normal in this respect, having the chloro group endo in the major product. These results are discussed in terms of the non-linear approach which carbenes and carbenoids may adopt when they are being inserted into double bonds.