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
作者:Paola Del Buttero、Giorgio Molteni、Antonio Papagni、Tullio Pilati
DOI:10.1016/s0040-4020(03)00778-6
日期:2003.7
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∗,5S∗)-4 and (4R∗,5R∗)-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
新型3-(2-氟-5-硝基)苯基-4-苯甲酰基-2-氮杂环丁烷酮3和7的硼氢化钠羰基还原反应定量得到立体异构的甲醇(4 R ∗,5 S ∗)- 4和(4 R *,5 R *)- 5。用氢化钠处理后者,分别以良好的总收率得到标题化合物8和9。序列3(或7)→ 4 → 8和3中概述的立体化学关系的基本原理根据反应物的构象和酮-烯醇平衡给出(或7)→ 5 → 9。