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Abstract

This invention provides a process for conducting Kumada coupling reactions. The processes of the present invention make use of N-heterocyclic carbenes as ancillary ligands in Kumada couplings of aryl halides. A Kumada coupling can be carried out by mixing, in a liquid medium, at least one aryl halide, wherein the aryl halide has, directly bonded to the aromatic ring(s), at least one halogen atom selected from the group consisting of a chlorine atom, a bromine atom, and an iodine atom; at least one Grignard reagent; at least one metal compound comprising at least one metal atom selected from nickel, palladium, and platinum, wherein the formal oxidation state of the metal is zero or two; and at least one N-heterocyclic carbene. One preferred type of N-heterocyclic carbene is an imidazoline-2-ylidene of the formula ##STR1## wherein R.sup.1 and R.sup.2 are each, independently, alkyl or aryl groups having at least 3 carbon atoms, R.sup.3 and R.sup.4 are each, independently, a hydrogen atom, a halogen atom, or a hydrocarbyl group. Homocoupling of aryl pseudohalides is also feasible using the processes of this invention.

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First Claim