Calix[4]arene alpha-aminophosphonic acids: asymmetric synthesis and enantioselective inhibition of an alkaline phosphatase.

[structure: see text] Chiral calix[4]arene alpha-aminophosphonic acids were obtained through diastereoselective Pudovik-type addition of sodium ethyl phosphites to the chiral calixarene imines, removal of chiral auxiliary groups, and mild dealkylation of phosphonate fragments. The diacids obtained show inhibitory activity toward porcine kidney alkaline phosphatase that depends considerably on the absolute configuration of the alpha-carbon atoms.