The Ni-Mediated Cyclocarbonylation of Allyl Halides and Alkynes Made Catalytic.Evidence Supporting the Involvement of Pseudoradical Ni~I Species in the Mechanism

摘要

Among the different pentannulation methods,the metal-mediated [2 + 2+1] carbonylative cycloadditions represent the most straightforward way to synthesize the cyclopentane skeleton since three C-C bonds are formed in a single experimental operation.The Pauson-Khand reaction,originally mediated by cobalt and later found to undergo in the presence of other metal complexes,fits within this strategy.In a similar approach,we have studied the scope and the selectivity arising from the Cyclocarbonylation of allyl halides and acetylenes mediated by nickel (a reaction which has precedents in the work of G.P.Chiusoli and W.Oppolzer) (Scheme 1).