Diastereoselective Oxidative Addition of Dihydrogen to IrI(CO)((R)-BINAP) and [Ir(CO)2((R)-BINAP)][SbF6]

Two chiral iridium(I) (R)-BINAP complexes, IrI(CO)((R)-BINAP) (1) and [Ir(CO)2((R)-BINAP)][SbF6] (2), have been synthesized and characterized, and their reactivity with dihydrogen has been studied. Complex 1 is formed on the addition of (R)-BINAP to [Bu4N][IrI2(CO)2] in toluene, and 2 is generated by the addition of AgSbF6 to a solution of 1 in dichloromethane under CO. A structure determination of complex 2 confirms a square planar coordination geometry, while that of 1 reveals a significant tetrahedral distortion from the expected planar coordination. Additionally, the structure of 1 shows a disorder between iodide and CO ligands. The reaction of 1 with H2 proceeds under kinetic control and shows a high degree of kinetic and thermodynamic selectivity; the kinetic product is formed by H2 addition across the P−Ir−CO axis of IrI(CO)((R)-BINAP) and yields two diastereomers which then convert over time to two more stable diastereomers which correspond to oxidative addition across the P−Ir−I axis. The kinetic...