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Chiral Scandium Catalysts for Enantioselective Michael Reactions of β‐Ketoesters
Author(s) -
Ogawa Chikako,
Kizu Keiko,
Shimizu Haruka,
Takeuchi Masahiko,
Kobayashi Shu
Publication year - 2006
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200600093
Subject(s) - scandium , enantioselective synthesis , catalysis , michael reaction , adduct , chemistry , bipyridine , organic chemistry , medicinal chemistry , crystal structure
A highly enantioselective Michael reaction of β‐ketoesters with α,β‐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 °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.