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.
US5219731A
申请人:——
公开号:US5219731A
公开(公告)日:1993-06-15
Rh(<scp>iii</scp>)-Catalyzed diastereoselective transfer hydrogenation: an efficient entry to key intermediates of HIV protease inhibitors
A highlyefficient diastereoselective transferhydrogenation of α-aminoalkyl α'-chloromethyl ketones catalyzed by a tethered rhodium complex was developed and successfully utilized in the synthesis of the key intermediates of HIV protease inhibitors. With the current Rh(iii) catalyst system, a series of chiral 3-amino-1-chloro-2-hydroxy-4-phenylbutanes were produced in excellent yields and diastereoselectivities