Ag⁺-Assisted Hydrosilylation:  Complementary Behavior of Rh and Ir Catalysts (Reversal of Enantioselectivity)

Abstract

[structure: see text]. The presence of a suitably situated hydroxy function in a PHOX ligand leads to an enhancement of the enantioselectivity in Rh-catalyzed hydrosilylations of prochiral ketones in the presence of AgBF4 (95% ee for acetophenone as compared to 75% using i-Pr-phosphinooxazoline (PHOX)). Exchanging Rh for Ir affords the product with the opposite absolute configuration (78% ee).