Highly active, air-stable palladium catalysts for the C-C and C-S bond-forming reactions of vinyl and aryl chlorides:: Use of commercially available [(t-Bu)2P(OH)]2PdCl2, [(t-Bu)2P(OH)PdCl2]2, and [[(t-Bu)2PO•••H•••OP(t-Bu)2]PdCl]2 as catalysts

Air-stable palladium complexes [(t-BU)(2)P(OH)](2)PdCl2, [(t-BU)(2)P(OH)PdCl2](2), and [[(t-Bu)(2)PO...H...OP(t-Bu)(2)]PdCl](2) serve as efficient catalysts for a variety of cross-coupling reactions of vinyl and aryl chlorides with arylboronic acids, arylzinc reagents, and thiols to yield the corresponding styrene derivatives, biaryls, and thioethers. P-31 NMR and mechanistic studies argue that the phosphinous acid ligands in the complexes can be deprotonated in the presence of a base to yield an electron-rich anionic species, which is likely a catalyst intermediate, and dimeric [[(t-BU)(2)PO...H...OP(t-Bu)(2)]PdCl](2) was isolated and cystallographically characterized. These anionic complexes are anticipated not only to accelerate the rate-determining oxidative addition of aryl chlorides but also to stabilize the palladium complexes in the catalytic cycle.