The cross-coupling reaction between an organometallic species and an organic halide is an important method for forming a new carbon ± carbon bond. Whereas transition metal catalyzed cross-coupling reactions between sp 2 carbon centers are well established [1] and routinely applied even in complex syntheses, [2] the cross-coupling reaction between two sp 3 carbon centers often requires the use of stoichiometric amounts of organocuprates, [3] which has several drawbacks. A nontransferred or nontransferable functional group is often wasted, and the moderate functional group diversity of lithium or magnesium cuprates [4] often limits their application. Recently, we have shown that the presence of a double bond in the position g to the carbon ± halogen bond considerably facilitates the reductive-elimination step of the crosscoupling. [5] The remote double bond coordinates to the nickel center and in this way removes electron density from the metal atom. [6] Although it is mechanistically interesting, the required presence of the double bond in the iodoalkane reduces the synthetic scope of the reaction. Herein, we report that the addition of catalytic amounts of an unsaturated additive such as 1 a allows an efficient [Ni(acac) 2 ]-catalyzed cross-coupling reaction to be performed between various polyfunctional organic halides 2 and diorganozinc compounds 3 to give the cross-coupling products 4 (Scheme 1); this considerably extends the scope of the reaction.
Scheme 1. Cross-coupling between sp 3 carbon centers in the presence of cocatalysts 1 a. FG functional group; NMP N-methylpyrrolidone.