Optically active 1-aromatic-group-substituted-1-alkanones and methods for their manufacture

A process for preparing an optically active alpha-aromatic group substituted alkanoic acid on its ester of the general formula:

• ##STR21## wherein Ar represents an aromatic group, R represents a saturated aliphatic group, R.sup.2 represents a hydrogen atom, an alkyl group or a hydroxyalkyl group, and * indicates an asymmetric carbon atom, or a pharmaceutically acceptable salt thereof, which comprises contacting an optically active alkane acid halide of the general formula:
• ##STR22## wherein X is a halogen atom or a sulfonyloxy group, Y is a halogen atom and R and * are as defined above, with an aromatic compound of the general formula:
• Ar--H
• wherein Ar is defined as above, in the presence of a Lewis acid, and rearranging the resulting 1-aromatic-group-substituted-1-alkanone to the corresponding alpha-aromatic-group-substituted alkanoic acid or its ester, and optionally converting a compound of formula II to its pharmaceutically acceptable salt.