A direct conjugate addition of simple alkenes to enones has been achieved in the presence of a Ni(0)/PCy(3) catalyst.

In the presence of a catalytic amount of Ni(cod)2 and PCy3, the reaction of (E)-1-phenylbut-2-en-1-one (1a) with ethylene occurred to give three-component addition products, 1,6-enone 2a and 1,5-diketone 4a. The reaction of an enone with two ethylenes gave 2a. The reaction of two enones with an ethylene gave 4a. On the other hand, 2-methyl-1-phenylprop-2-en-1-one (1b) reacted with two ethylenes selectively to give a mixture of 2b and 3b. The reaction might proceed via oxidative cyclization of an enone and an ethylene with nickel(0).

Nickel-Catalyzed Conjugate Addition of Simple Alkenes to Enones. -The direct conjugate addition of simple alkenes to enones is a very straightforward method for the introduction of an alkenyl group at the β-position. Conventional methods require the preparation of alkenyl metal compounds. -(OGOSHI*, S.; HABA, T.; OHASHI, M.;

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