Changmin Bai

Highly enantioselective resolution of terminal epoxides using polymeric catalysts

Poly-salen-Co(III) complexes were employed in the hydrolytic kinetic resolution (HKR) of terminal epoxides and ees up to 98% were obtained. In the HKR of epichlorohydrin, the polymeric catalysts can be recovered and modified for recycling. The recovered polymer catalyst shows good activity and selectivity.

Ferrocenylphosphine-imine ligands for Pd-catalyzed asymmetric allylic alkylation

Ferrocenylphosphine-imine ligands 6 derived front (r,s)-ppfnh2-r 5 and a variety of benzaldehydes were applied in the pd-catalyzed asymmetric allylic alkylation of 1,3-diphenylprop-2-en-1-yl acetate 7a or pivalate 7b with dimethyl malonate. the substituent effects on the catalytic reaction were investigated, and 96% e.e. with 99% yield was achieved when the m-nitro substituted ligand 6k was used. (c) 2002 elsevier science ltd. all rights reserved.

New efficient P,N,O-tridentate ligands for Ru-catalyzed asymmetric transfer hydrogenation

Abstract New chiral P,N,O Schiff base ligands derived from substituted salicylaldehyde and ( R )-1-[( S )-2-(diphenylphosphino)-ferrocenyl]ethylamine[( R , S Fc )-PPFNH 2 ] have been prepared and employed in ruthenium catalyzed asymmetric transfer hydrogenation of simple ketones. Up to 94% e.e. with 99% conversion was obtained when the electron-withdrawing 3,5-dinitro substituted ligand 2f was used.

Structural probing of d-fructose derived ligands for asymmetric addition of diethylzinc to aldehydes

Abstract A series of new chiral ligands derived from d -fructose have been synthesized and applied in the enantioselective addition of diethylzinc to aldehydes. Comparison of the enantioselectivities obtained with these ligands demonstrated that the catalytic properties are highly dependent upon the structure of ligands, a rational explanation of the structural effects on the catalytic properties is provided.

Highly enantioselective resolution of terminal epoxides with cross-linked polymeric salen-Co(III) complexes

Abstract Crosslinked polymeric salen–Co(III) complexes derived from a novel dialdehyde and a trialdehyde were synthesized and employed in the hydrolytic kinetic resolution (HKR) of terminal epoxides. Up to 99% ee were obtained with only 0.16–0.02 mol% of catalyst (based on catalytic unit).

Synthesis of novel ferrocenylphosphine-amidine ligands and their application in Pd-catalyzed asymmetric allylic alkylation

A family of novel ferrocenylphosphine-amidine ligands derived from (R)-(S)-PPFNH2-R 5 was applied to the palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenylprop-2-en-1-yl acetate 8a or pivalate 8b with dimethyl malonate. Up to 94% e.e. was achieved when ligand 6b was used

New chiral ferrocenyldiphosphine ligand for catalytic asymmetric transfer hydrogenation

New chiral ferrocenyldiphosphine ligands (R)-(S)-3 and (R)-(S)-4 were prepared. The ligands were employed in Ru(II) catalyzed asymmetric transfer hydrogenation of ketones to give corresponding secondary alcohols. Up to 99% conversion with 90% e.e. was obtained on Ru(DMSO)(4)Cl-2/4 in transfer hydrogenation of acetophenones with propan-2-ol

Readily available new pyridyl alcohols derived from d-glucose as ligands for the enantioselective addition of diethylzinc to aldehydes

Abstract A series of new chiral ligands derived from d -glucose has been synthesized and applied in the enantioselective addition of diethylzinc to aldehydes. Up to 94.1% e.e. was obtained in the ethylation reactions. In contrast to the ligands derived from d -fructose, ligands derived from d -glucose gave the opposite asymmetric induction.