Glycosylation‐Induced and Lewis Acid‐Catalyzed Asymmetric Synthesis of β‐ N ‐Glycosidically Linked α‐Aminophosphonic Acids Derivatives

The diastereospecific formation of β‐ N ‐glycosidically linked α‐aminophosphonic acids derivatives has been achieved with high yield via a Mannich‐type reaction. The reaction was performed by using O ‐pivaloylated galactosylamine 1 as a chiral template and boron trifluoride diethyl etherate as a catalyst in THF. Imines 3 of aromatic compounds and diethyl phosphite were converted to N ‐galactosyl α‐aminoalkylphosphonate 4 , giving ratios of diastereomers higher than 19:1. This procedure provides a rapid access to biologically important galactosyl α‐aminophosphonic acids derivatives.