A process for the preparation of 2-aryl-2-alkyl-malonic acids

The invention relates to a process for the preparation of 2-aryl-2-alkyl-malonic acids of formula in which RX R is hydrogen (H), methyl, ethyl, propyl, n-butyl or isopropyl radical, and X is fluorine, chlorine, nitro, methoxy and ethoxy radical at any position of R, and Y-aryl Aryl is phenyl, naphthyl, biphenyl or benzoylphenyl radical, and Y is hydrogen (H-), fluoro, chloro, nitro, methoxy, ethoxy, and methyl, ethyl, propyl, n-isopropyl or butyl radical from corresponding 2-aryl-alkanoic acids which satisfy the following formula: wherein X is alkyl, Y and aryl have the same meaning, and before and after reaction do not change, as an intermediate for the preparation of optically pure 2-aryl-alkanoic acids from the racemates or enantiomerically pure 2-aryl-alkanoic acids. The invention is characterized by characterized by esterifying the carboxylic acid moiety to a benzyl ester, converting the benzyl ester in a malonic acid dibenzyl ester by addition of benzyl chloroformate in the presence of a strong base for the deprotonation of the chiral C-atom, hydrogenating the Malonsauredibenzylesters to the free acid.