✦ LIBER ✦
The intramolecular aromatic nucleophilic substitution as a route to tricyclic β-lactams. Synthesis of the novel 4-oxa-7-azabicyclo[4.2.0]octane skeleton
✍ Scribed by Paola Del Buttero; Giorgio Molteni; Antonio Papagni; Tullio Pilati
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- French
- Weight
- 150 KB
- Volume
- 59
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
Sodium borohydride-carbonyl reduction of the novel 3-(2-fluoro-5-nitro) phenyl-4-benzoyl-2-azetidinones 3 and 7 gave quantitatively the stereoisomeric carbinols (4R p ,5S p )-4 and (4R p ,5R p )-5. Treatment of the latter with sodium hydride gave the title compounds 8 and 9, respectively, with good overall yield. The rationale of the stereochemical relationships outlined in the sequences 3 (or 7)!4!8 and 3 (or 7)!5!9 is given according to the conformational and keto-enol equilibria of the reactant(s).