Diastereoselective Synthesis of Adjacent P,C-Stereogenic β‑N‑Glycosidic Linked α‑Aminophosphinates

The diastereoselective formation of adjacent P,C-stereogenic β-N-glycosidic linked α-aminophosphinates is developed in high yields via a phospha-Mannich reaction. The reaction was performed by employing (Rp)-O-(−)-menthyl H-phenylphosphinate and O-pivaloylated N-galactosylimine for double stereodifferentiation and BF3·Et2O as a promoter in THF. O-Pivaloylated N-galactosylphenyl imine 2 and (Rp)-O-(−)-menthyl H-phenylphosphinate 1 were converted to N-galactosyl α-aminoalkylphosphinate 3 with ratios of diastereomers up to 20:1. The synthetic method of the conversion provides a rapid access to adjacent P,C-stereogenic chiral α-aminophosphinates.