Preparation of chlorofluoroacetic acid derivatives for the analysis of chiral alcohols

(R)- and (S)- Chlorofluoroacetic acid (CFA) esters of several chiral secondary alcohols have been prepared and compared with the corresponding esters of Mosher's acid. CFA itself is a readily accessible and optically stable acid which gives the expected diastereoisomeric products with chiral alcohols without epimerization. The resulting diastereoisomers are more volatile than those derived from Mosher's acid, and are well resolved by both GC and HPLC. Both H-1 and F-19 NMR spectra of CFA esters show characteristic signals in regions rarely overlapped by other signals. Since CFA is a strong organic acid, it reacts with alcohols spontaneously to give esters without any additional catalysis