Synthesis of optically active hydroxyphosphonates
Abstract
The reduction of dimenthyl ketophosphonates with sodium borohydride involves asymmetric induction at the α-carbon atom, resulting in a small excess of the (R)-enantiomer of the α-hydroxyphosphonate formed. A higher ee purity was achieved if the reduction of chiral dimenthyl ketophosphonates was carried out by the chiral complex of NaBH4-L-proline, owing to the double asymmetric induction at the α-carbon atom. The hydroxyphosphonates obtained were isolated in a diastereomerically pure state and were transformed to the optically active, free hydroxyalkylphosphonic acids. The (R)-configuration of one of them was proved by X-ray crystal structure analysis. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:133–139, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20391
