Diastereoselective Synthesis of Bicyclic γ-Lactams via Ring Expansion of Monocyclic β-Lactams
作者:Stijn Dekeukeleire、Matthias D’hooghe、Norbert De Kimpe
DOI:10.1021/jo802459j
日期:2009.2.20
with 1 equiv of AgBF4 and pyridine in toluene via intramolecular nucleophilic trapping of N-acyliminium intermediates by the hydroxyl moiety. Additionally, the corresponding aza-analogues of the aforementioned bicyclic γ-lactams (i.e., trans-1,4-diazabicyclo[3.3.0]octan-8-ones and trans-1,5-diazabicyclo[4.3.0]nonan-9-ones) were prepared in a convenient way starting from cis-4-(1-chloro-1-methylethyl
顺式-4-(1-氯-1-甲基乙基)-1-(ω-羟烷基)氮杂环丁烷-2-酮经非对映选择性转化为新型反式-1-氮杂-4-氧杂双环[3.3.0] octan-8-酮。和反式-1-氮杂-5-氧杂二环[4.3.0]壬烷-9-酮在治疗与1个当量的AgBF的4通过的分子内亲核捕集和吡啶在甲苯ñ由羟基部分-acyliminium中间体。另外,上述双环γ-内酰胺的相应氮杂类似物(即,反式-1,4-二氮杂双环[3.3.0] octan-8-和反式-1,5-二氮杂双环[4.3.0] nonan-9 -)是从cis -4-(1-chloro-1-methylethyl)-1- ω-[(tert-丁氧基羰基)氨基]烷基}氮杂环丁烷-2-酮采用相同的反应条件。通过起始β-内酰胺的环膨胀,通过产生瞬态的银(I)诱导的碳正离子,形成中间的N-酰基亚胺离子。