Chiral Fluorophosphonomethylbenzaldehydes

摘要

We synthesized some optically active alpha-fluoro-phosphonates II and III,which are of interest as chiral synthetic blocks for preparing potentially biologically active compounds and phosphorus analogs of natural compounds.Optically active hydroxyphosphonates(1S)-I and(1R)-I synthesized as described in [1] were reacted with(diethylamino)trifluorosulfurane at room temperature or under mild cooling.The reaction was accompanied by full racemization.However,we found that the reaction of hydroxyphosphosphonates I,containing menthyl groups at the phosphorus atom,with diethylaminotrifluorosulfurane at a low temperature(-80°C)in methylene chloride results in muchlower degree of racemization.