Synthetic studies on carbapenem antibiotics from penicillins.II. regio- and stereoselective aldol reaction of a chiral azetidinone: a synthesis of optically active 6-epicarpetimycins
✍ Scribed by Hideo Hiraia; Kozo Sawada; Matsuhiko Aratani; Masashi Hashimoto
- Publisher
- Elsevier Science
- Year
- 1984
- Tongue
- French
- Weight
- 267 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Aldol and alkylation reactions of the chira1 4-allylazetidinone I gave 3,4-trans-azetidinones as major products, in which 10 was converted in severa1 steps to the optically active ó-epicarpetimycins 2. Considerable effort has been directed recently toward the total synthesis of chira1 carbapenem antibiotics3. As part of our continuing program on B-lactam antibiotics, we have concentrated on the synthesis of optically active carbapenems by utilization of the penicillin B-lactam as a chira1 precursor. In the preceding paper', we described the stereospecific synthesis of 4-allylazetidinones from penicillins, which allowed the introduction of the chira1 functionality necessary for construction of the optically active carbapenem ring system. In most of the carbapenem antibiotics, the relative stereochemistry at C-3 and C-4 of the 8-lactam ring is trans except few examples of the cis stereochemistry in the case of such as carpetimycins 3f.4