UNUSUAL AMINO-ACIDS .3. ASYMMETRIC-SYNTHESIS OF 3-ARYLALANINES

21 (Z)-alpha-N-benzoylamino-beta-arylacrylic acids and their esters were prepared by known procedures and hydrogenated to the corresponding optically active alpha-benzoyl-beta-arylalanine derivatives with optical yields in the range of 82-95% ee using the cationic rhodium complex of ''PROPRAPHOS'' as the chiral catalyst No electronical influences of the substituents at the aryl moiety on the enantioselectivity were observed but a sterical one, proved by X-ray crystallographic analysis and computer-aided modellings. Deacylation of the hydrogenated spezies produced the hydrochlorides of the 3-arylalanines attended by a partial racemisation In this case the hydrogenation of urethane type protected dehydroaminoacid derivatives seems to be the alternative.