what is a cross-coupling reaction?

directory of Chem Help ASAP videos: https://www.chemhelpasap.com/youtube/ A cross-coupling reaction is any reaction in which two different partners are joined together. In general, reactions called cross-coupling reactions involve a transition metal catalyst, often palladium. The catalyst joins an aryl halide with an aryl metal to form a biaryl product. The reactions in this playlist all approximately fit this profile and include the Negishi, Stille, Suzuki, Sonogashira, and Buchwald-Hartwig reactions.