Ni-promoted Cyclopentenone Formation by Intramolecular Cyclocarbonylation of 1-Bromo-1,4-dienes

Article abstract of DOI:10.1016/S0040-4020(01)85818-X

Stereoselective syn addition of allyl bromide to acetylenes catalysed by palladium(II) bromide results in the formation of 1-bromo-1,4-dienes which were further converted to cyclopentenones through a Ni(CO)4 promoted carbonylation-cyclization process.Four C-C bonds are formed by this two step sequence, leading to 2,3-substituted 5-methoxycarbonylmethylcyclopentenones 1.Application of this procedure to 2-butyne affords cyclopentenone 1c, an immediate precursor of the antibiotic methylenomycin B.