作者:Hsiao Chi-Nung、Stephen P. Ashburn、Marvin J. Miller
DOI:10.1016/s0040-4039(00)94969-4
日期:1985.1
The compatability of an acyl thiazolidine thione as a chiral auxillary in boron enolate chemistry has been demonstrated by an enantioselective aldol condensation. The aldol products provide direct access to chiral β-lactams.
Process for intermediates to 1-carbapenems and 1-carbacephems
申请人:THE UNIVERSITY OF NOTRE DAME DU LAC
公开号:EP0218415A1
公开(公告)日:1987-04-15
A stereoselective process for chiral intermediates to 1-carbapenem and 1-carbacephalosporins is provided comprising the use of an N-acyl(4R)substituted-1,3-thiazolidine-2-thione as a chiral auxiliary in boron enolate mediated aldol condensation with a protected-β-keto ester aldehyde. Benzyl 3,3-(ethylenedioxy)-4-formylbutyrate is condensed with the boron enolate formed with nbutyryl (4R)-methoxycarbonyl-1,3-thiazolidine-2-thione to provide benzyl 3,3-ethylenedioxy-(5R)-hydroxy-6-[(4R)-methoxycarbonyl-1,3-thiazolidine-2-thione-3-ylcarbonyl]octanoate. Displacement of the thiazolidine-2-thione chiral auxiliary moiety with an O-alkyl, O-acyl or O-aralkyl hydroxyamine provides the corresponding chiral intermediate as the hydroxamate.