The application of asymmetric ketene-imine cycloadditions to the first enantioselective synthesis of the carbacephalosporin nucleus is described.
The asymmetric synthesis of β-lactam antibiotics - III. Enantioselective synthesis of (+) PS-5
✍ Scribed by David A Evans; Eric B Sjogren
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- French
- Weight
- 241 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0040-4039
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📜 SIMILAR VOLUMES
Oxidative cleavage of crotonate imide aldol adduct 6b provides the configurationally stable aldehyde 4. Transformation of this aldehyde to enantiomerically pure p-lactams is described.
a-Thioformamido-diethylphosphonoacetates (I) have been found to condense with lcbloro-2-propanones in the presence of base to give 6H-1,3-thiazine-4-carboxylates (II).
An enantioselective synthesis of the carbapenem antibiotic (+)-ps-5 is described. The starting point is the chiral Sharpless epoxyalcohol 2 which is transformed stereospecifically to the eziridine 6. Regioeelective ring-ope&ng of 6 by'LiEt Cu followed by RuQ oxidation yields the @-sulfonamide cat-bo