NEW ROUTES TO DIETHYL 1-FLUOROMETHYLPHOSPHONOCARBOXYLATES AND DIETHYL1-FLUOROMETHYLPHOSPHONOCARBOXYLIC ACID

Diethyl 1-fluoromethylphosphonocarboxylic esters 4, bearing a variety of ester groups (alkyl, aryl), have been conveniently prepared in a on e-pot process, by reaction of chloroformates with ithio-1-fluoro-1-(tr imethylsilyl)methylphosphonate 2 derived from 1,1-dibromo-1-fluorometh ylphosphonate 1. The overall yields generally range from 80 to 91%. Re action of 2 with CO2 leads to a novel efficient synthesis of diethyl 1 -fluoromethylphosphonocarboxylic acid 7 in 86% yield. (C) 1997 Elsevie r Science Ltd.