Rhodium catalyzed asymmetric chiral 1,4 diphosphine ligands

The development of chiral catalysts for use in enantioselective rhodium-catalyzed hydroborations was pioneered by Burgess9, Suzuki,77 and Hayashi.78 The chiral diphosphine ligands employed in their preliminary investigations 23-26 (Figures 2(a) and 2(b)), had previously been successfully applied in other catalytic asymmetric transformations. 

Mori, R, Fukawa, N., Noguchi, K., Tanaka, K. (2011). Asymmetric synthesis of axially chiral biaryl diphosphine ligands by rhodium-catalyzed enantioselective intramolecular double [2+2+2] cycloaddition. Organic Letters, 13, 362-365. 

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