Chiral scandium catalysts for enantioselective Michael reactions of beta-ketoesters.
A highly enantioselective Michael reaction of beta-ketoesters with alpha,beta-unsaturated ketones promoted by a chiral scandium catalyst has been developed. In the presence of Sc(OTf)3 and (S,S)-6,6'-bis(1-hydroxy-2,2'-dimethylpropyl)-2,2'-bipyridine, the desired Michael reactions proceeded smoothly in dichloroethane at 40 degrees C to afford the corresponding adducts in good to high yields with excellent enantioselectivities in most cases. It was found in this reaction that a lower concentration of the reaction mixture was key to attaining high enantioselectivities.
Ogawa
Chikako
C
Graduate School of Pharmaceutical Sciences, The University of Tokyo, The HFRE Division, ERATO, Japan Science Technology Agency, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Kizu
Keiko
K
Shimizu
Haruka
H
Takeuchi
Masahiko
M
Kobayashi
Shu
S
D002384:Catalysis; D004952:Esters / Q000737:chemistry*; D012538:Scandium / Q000737:chemistry*; D013237:Stereoisomerism
D004952:Esters; D012538:Scandium