Novel chiral sulfinamide phosphines: valuable precursors to chiral β-aminophosphines

Starting from commercially available aldehyde and chiral tert-butanesulfinamide, a series of chiral sulfinamide phosphines (Xiao-Phos) were synthesized via a two-step condensation-nucleophilic addition procedure. In most cases, nucleophilic addition of the N-tert-butanesulfinyl imine with diphenyl methyl phosphonic lithium showed high diastereoselectivity (d.r>20:1) with BF3 as additives. Following removal of the chiral auxilliary, an important class of ligands i.e chiral β-aminophosphines and its derivatives were obtained in high yields using this approach.