Nickel-catalyzed carbonylative four-component 1,4-dicarbofunctionalization of 1,3-enynes

An efficient Ni-catalyzed four-component 1,4-carbocarbonylation of 1,3-enynes with activated alkyl halides and arylboronic acids under atmospheric pressure of CO is presented. By tuning the electronic and steric effects of alkyl radicals, both electron-rich and electron-deficient 1,3-enynes were compatible with this cascade. This protocol features mild conditions, broad substrate scope, excellent functional group compatibility and facile gram-scale synthesis, providing a practical approach to the quaternary carbon center-containing allenyl ketones. Mechanistic study revealed that the acyl-Ni^II species plays an important role in both the coupling and the alkyl radical generation processes.