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The First Catalytic Asymmetric Addition of Dialkylzincs to α-Ketoesters

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journal contribution
posted on 09.10.2002, 00:00 by Erin F. DiMauro, Marisa C. Kozlowski
The first catalytic, enantioselective addition of organozinc reagents to α-ketoesters is described. Modular bifunctional salen catalysts that contain Lewis acid and Lewis base activating groups accelerate the carbonyl addition to a much greater extent than the competing carbonyl reduction. α-Hydroxyesters containing new quaternary stereogenic centers are obtained in high yield and moderate enantiomeric excess. Enrichment to 98% ee can be effected by recrystallization of the corresponding α-hydroxy acid.