Ligand-Promoted Oxidative Cross-Coupling of Aryl Boronic Acids and Aryl Silanes by Palladium Catalysis

The first cross-coupling reaction between aryl silanes and aryl boronic acids is described. This transformation represents one of the very few examples of coupling reactions between two nucleophilic organometallic reagents and provides a new method for the formation of biaryl compounds. The successful development of this reaction was enabled by the use of commercially available 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) as the ligand. A small amount of BINAP (3 mol%) was sufficient to suppress the formation of the homocoupling products, and the reaction yielded the cross-coupling products with high selectivity under mild conditions, even when the ratio of the two coupling partners was 1:1.