The [2+ 2] and [2+ 4] cycloadditions of difluoromethylenecyclopropanes

WR Dolbier Jr, M Seabury, D Daly…

Index: Dolbier, William R.; Seabury, Mark; Daly, Daniel Journal of Organic Chemistry, 1986 , vol. 51, # 7 p. 974 - 979

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Citation Number: 29

Abstract

The [2+ 21 cycloaddition reactions of methylenecyclopropanes are presumed to proceed via a two-step, biradical mechanism wherein the first step involves a-bond formation to the highly strained sp2-hybridized carbon of the methylenecyclopropane to give the most stable biradical intermediate, which determines the favored regiochemistry. 5 This mechanism is exemplified in eq 3 for the reaction of (dichloromethy1ene) cyclopropane with butadi-