A novel, double-asymmetric aldol approach to the synthesis of a 1β-methyl carbapenem antibiotic precursor
作者:Fumiyuki Shirai、Takeshi Nakai
DOI:10.1016/s0040-4039(00)82373-4
日期:1988.1
A novel synthetic approach to the 1β-methyl carbapenem key precursor is described which involves the chelation-controlled double-asymmetric aldol reaction as the key step.
The Eu(III)-catalyzed reaction of alpha-benzyloxyaldehydes with the (R)-3-hydroxybutanoate-derived ketene silyl acetal is shown to provide a higher level of both ''anti'' diastereofacial selection and rather unusual anti diastereoselection, compared with the conventional TiCl4-promoted version. The aldol adducts are elaborated to the carbapenem intermediates.
SHIRAI, FUMIYUKI;GU, JIN-HUA;NAKAI, TAKESHI, CHEM. LETT.,(1990) N0, C. 1931-1934
作者:SHIRAI, FUMIYUKI、GU, JIN-HUA、NAKAI, TAKESHI
DOI:——
日期:——
Diastereofacial Selection in Titanium Tetrachloride-Promoted Aldol Reactions with the Silyl Ketene Acetal of Methyl (<i>R</i>)-3-Hydroxybutanoate
作者:Fumiyuki Shirai、Jin-Hua Gu、Takeshi Nakai
DOI:10.1246/cl.1990.1931
日期:1990.10
The title reaction is shown to exhibit a high level of “anti” diastereofacial selection, in contrast to the “syn” selection observed for the reaction with the dilithium enolate of the chiral ester. Mechanistic grounds for the “anti” stereoselection are discussed.