GENERATION AND TRAPPING OF VINYLCARBENES AT AMBIENT TEMPARATURE: A ROUTE TO FUNCTIONALISED VINYL- AND ALLYLIDENE CYCLOPROPANES

Article abstract of DOI:10.1016/S0040-4020(01)89222-X

1,2-Dehalogenation of tetrachlorocyclopropanes (5, X = Cl, OMe, N-iPr2, SAllyl) by methyl lithium leads to dichlorocyclopropenes ( 6, X = Cl, OMe, i-NPr2, SAllyl); the first two of these react with electron rich and electron poor alkenes at 20 deg C to give cyclopropanes which are apparently derived by trapping of vinylcarbenes (8) rather than (20).Reaction of the derived vinylcyclopropanes with base leads either to ethyl cyclopropyl ketones or to allylidenecyclopropanes.