A chiral diphosphine containing hemilabile ether donor groups and its use in rhodium asymmetric hydroboration of styrene

The new homochiral diphosphine (R,R)-o-C6H4[CH2OCH2CH(Me)PPh2](2) (1) was p repared from ethyl lactate in five steps. Because of the two hemilabile eth er groups, the ligand can be visualized as a diphosphine containing two int ramolecular solvent molecules. The cationic Rh(I) complex [Rh(1)] (BF4) was prepared and used as the catalyst in the asymmetric hydroboration of styre ne with catecholborane. The catalytic system is chemo- and regioselective, but it yields low enantiomeric excess. (C) 1999 Elsevier Science S.A. All r ights reserved.