TRANSITION METAL CATALYZED REACTIONS OF DIAZOESTERS; CYCLOPROPANATION OF DIENES AND TRIENES

Article abstract of DOI:10.1016/S0040-4020(01)91934-9

The regioselectivity of the cyclopropanation of polyenes by cycloaddition of carbenes generated by catalysed decomposition of diazoesters in the presence of Rh, Pd and Cu catalyst can be controlled to some extent by selecting proper rection parameters.For a particular diene, the regioselectivity depends both on the catalyst and on the nature of the double-bond (conjugation, substitution).The cyclopropanation of trienes containing both a conjugated diene system and an isolated double bond is reported as an application of these reactions.The practical interest of the present study is further demonstrated by the synthesis of a pyrethroid precursor by the rhodium(II) carboxylates catalyzed-cyclopropanations of 1,1-dichloro-4-methyl-1,3-pentadiene.