THE PREPARATION OF MIXTURES OF (R)- AND (S)-2-(4-ALKANOYLPHENOXY)- OR (R)- AND (S)-2-(4-AROYLPHENOXY)PROPIONIC ESTERS

摘要

PCT No. PCT/EP94/01684 Sec. 371 Date Aug. 11, 1995 Sec. 102(e) Date Aug. 11, 1995 PCT Filed May 26, 1994 PCT Pub. No. WO94/27950 PCT Pub. Date Dec. 8, 1994A mixture of (R)- and (S)-2-(4-alkanoylphenoxy)- or (R)- and (S)-2-(4-aroylphenoxy)propionic esters I I with an enantiomeric excess of at least 90% is prepared by reacting a mixture of (R) and (S) enantiomer of a 2-phenoxypropionic ester II II in which the appropriate (R) or (S) isomer is present in excess, with a carboxylic acid derivative of the formula III R1-CO-X III, (X=OH, halogen, R1COO or sulfonyloxy) in the presence of a Friedel-Crafts catalyst. The (R)- or (S)-2-(4-alkanoylphenoxy)propionic esters and (R)- or (S)-2-(4-hydroxyphenoxy)propionic esters are used for preparing crop protection agents and drugs.