The Negishi cross-coupling reaction is the organic reaction of an organohalide with an organozinc compound to give the coupled product using a palladium or nickel catalyst. The palladium catalyzed mechanism begins with oxidative addition of the organohalide to the Pd(0) to form a Pd(II) complex. Transmetalation with the organozinc then follows where the R group of the organozinc reagent replaces the halide anion on the palladium complex and makes a zinc(II) halide salt. Reductive elimination then gives the final coupled product, regenerates the catalyst, and the catalytic cycle can begin again.
King, A. O.; Okukado, N.; Negishi, E. J. Chem. Soc., Chem. Commun. 1977 683–684.