An Organocatalyst Bearing Stereogenic Carbon and Sulfur Centers as an Efficient Promoter for Enantioselective Hydrosilylation of 1,4-Benzooxazines

The efficient and enantioselective hydrosilylation of 3-aryl-1,4-benzooxazines was achieved using an l-phenyl alanine derived new Lewis base catalyst bearing stereogenic carbon and sulfur centers. In the presence of 2 mol % of catalyst, a broad range of 3-aryl-1,4-benzooxazines were hydrosilylated to afford the corresponding chiral 3-aryl-3,4-dihydro-2H-1,4-benzooxazine products with good to high yields (66–98%) and enantioselectivities (70–99% ee). This method provides an alternative approach with great practical application potential to access chiral 3-aryl-3,4-dihydro-2H-1,4-benzooxazines.