Palladium-catalysed P-C bond forming reactions between diphenylphosphine and ortho-substituted aryl bromides

Abstract

The use of palladium catalysts derived from 1,1'-bis-diisopropylphosphino- ferrocene and a microwave heating source allows the coupling of a rangeof ortho-substituted aryl bromides to diphenylphosphine derivatives to proceed in good yield in under 30 min. Optimization studies reveal that the combination of diphenylphosphine and DABCO is superior to more basic phosphide nucleophilessuch asPh2PK or Ph2PMgBr. High yields are only observed when moderately bulky electron rich diphosphines are used as ligands. The differences between P-C coupling and other cross-coupling reactions are discussed in the light of the reactivity observed. Studies aimed at producing industrially important 1,2-bis-phosphino-benzene ligands are also described.© 2009 John Wiley & Sons, Ltd.