Chi-Hung Yeung

New 1,3-amino alcohols derived from ketopinic acid and their application in catalytic enantioselective reduction of prochiral ketones

Abstract New 1,3-amino alcohols, (1 S ,2 S )- and (1 S ,2 R )-1-hydroxylmethyl-2-amino-7,7-dimethyl bicyclo[2,2,1]heptane ( endo - 4 and exo - 4 ), were prepared from ketopinic acid via oximation and reduction. The enantioselective borane reduction of prochiral ketones catalyzed by the borane complex of exo - 4 was examined.

An efficient synthesis of chiral homophenylalanine derivatives via enantioselective hydrogenation

Abstract Chiral homophenylalanine derivatives were synthesized via enantioselective hydrogenation of 5a and 5b catalyzed by rhodium complexes bearing chiral phosphine and phosphinite legands. Enantiomeric excesses up to 96.2% were achieved when S -spiroOP( S -1) was used as a chiral ligand under 500 psi of H 2 pressure in acetone.

AN IMPROVED SYNTHESIS OF CHIRAL DIOLS VIA THE ASYMMETRIC CATALYTIC HYDROGENATION OF PROCHIRAL DIONES

Abstract The rates of the asymmetric hydrogenation of prochiral diketones catalyzed by Ru(BINAP) catalysts were substantially accelerated in the presence of small amounts of a strong acid.

Asymmetric hydrogenation of dehydroamino acid derivatives catalyzed by a new aminophosphine phosphinite ligand derived from ketopinic acid

Abstract A new chiral aminophosphine phosphinite N , O -bis(diphenylphosphino)-(1 S ,2 R )-1-( N -methylamino) methyl-2-hydroxyl-7,7-dimethylbicyclo[2.2.1]heptane was synthesized from ketopinic acid and its application to the asymmetric hydrogenation of dehydroamino acid derivatives examined.