The First Applications of Carbene Ligands in Cross-Couplings of Alkyl Electrophiles:  Sonogashira Reactions of Unactivated Alkyl Bromides and Iodides

A Pd/N-heterocyclic carbene-based catalyst achieves the Sonogashira coupling of an array of functionalized, beta-hydrogen-containing alkyl bromides and iodides under mild conditions. By furnishing the first example of a nonphosphine-based palladium catalyst for cross-coupling unactivated alkyl electrophiles, this study provides an impetus for future efforts at catalyst development that extend beyond phosphine ligands.