Rhodium(I)-Catalyzed Highly Enantioselective Insertion of Carbenoid into Si-H: Efficient Access to Functional Chiral Silanes

The first rhodium(I)-catalyzed enantioselective Si-H insertion reaction of alpha-diazoesters and alpha-diazophosphonates has been developed. The use of a C-1-symmetric chiral diene ligand enabled the asymmetric reaction to proceed under exceptionally mild conditions and give versatile chiral a-silyl esters and phosphonates with excellent enantioselectivities (up to 99% ee). The mechanism and stereothemical pathway of this novel Rh(I)-carbene-directed Si-H insertion was investigated by deuterium kinetic isotope effect experiments and DFT calculations.