J. Am. Chem. Soc.; 2007, 129, 3844 - 3845.
DOI: 10.1021/ja070830d
Summary: Biaryl compounds are important structural elements in natural products and medicinally useful drug substances. This paper reports a useful advance in the palladium-catalyzed Kumada-Corriu biaryl cross-coupling reaction. The significance of this work is derived from the ability to conduct the reactions at low temperature (-20 to -65 deg C). This was made possible by (i) the application of Knochel's methodology, to form the desired Grignard reagents, containing in many cases reactive functional groups on the aromatic ring and (ii) the proper choice of biaryl phosphine ligand. Martin and Buchwald were able to take advantage of this chemistry and and prepare a variety of biaryl compounds including heterocyclic and polyfluoro biaryls. Screening of aryl iodides and triflates with various ligands revealed that superior conditions utilized aromatic iodides in conjunction with either DavePhos or S-Phos. Nitriles, esters, acetals, and amines are compatible under these conditions.
21 examples: 55-96% yield
