Bedford s catalysts

Several excellent papers reported by Bedford s group [123-130] dealing with very active palladium catalysts 337-340 show the great improvements in the SM reaction catalysis. The Bedford s catalysts are effective in the SM (and also Heck [123], and Stille [128]) reactions of aryl bromides (TON S up to 1 000 000 at 0.0001 mol%) [124,126], aryl chlorides (TON s up to 99 000 at 0.001 mol%) [125,127], both activated and unactivated, to afford the respective biaryls in good to high yields. For example, catalyst 339 was used in the SM reaction of (deactivated) 4-chloroanisole and phenylboronic acid to give 4-methoxybiphenyl with quantitative conversion at only 0.0015 mol% loading and TON of 33 000, respectively [127],... 

The second generation contains highly active palladium-catalysts, including the Bedford s and some other catalysts. 

Bedford RB, Betham M, Caffyn AJM, Charmant JPH, Lewis-Alleyne LC, Long PD, Polo-Cer6n D, Prashar S (2008) Simple rhodium-chlorophosphine pre-catalysts for the ortho-arylation of phenols. Chem Commun 990-992... 

Bedford, R.B., Cazin, C.S.J. and Holder, D. (2004) The development of palladium catalysts for C-C and C-heteroatom bond forming reactions of aryl chloride substrates. Coord. Chem. Rev., 248, 2283-321. 

Care must be taken in evaluating claims of activity for many metals, as traces of other metals may be the responsible catalyst Buchwald, S. L. Bohn, C. Angew. Chem., Int. Ed. 2009, 48, 5586 Bedford, R. B. Nakamura, M. et al. 

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