Tandem Polar/Radical Crossover Sequences for the Formation of Fused and Bridged Bicyclic Nitrogen Heterocycles Involving Radical Ionic Chain Reactions, and Alkene Radical Cation Intermediates, Performed under Reducing Conditions: Scope and Limitations
作者:David Crich、Krishnakumar Ranganathan、Santhosh Neelamkavil、Xianhai Huang
DOI:10.1021/ja035639s
日期:2003.7.1
anion contact ion pairs which are trapped intramolecularly in a tandem polar/radical crossover sequence involving radical ionic chain reactions by allylic and propargylic amines. The substitution pattern of the alkene radical cation dictates the cyclization mode, and this may be engineered to form fused ring systems by an initial exo-mode nucleophilic cyclization or bridged bicyclic systems when the nucleophilic
经证明,β-硝基醇的磷酸化形式在回流时暴露于苯中的三丁基氢化锡和 AIBN 时提供了进入 β-(磷酸酯氧基)烷基的极好方法。然后这些自由基经历磷酸基团的异裂裂解以产生烯烃自由基阳离子/磷酸根阴离子接触离子对,它们在串联极性/自由基交叉序列中被分子内捕获,涉及烯丙胺和炔丙胺的自由基离子链反应。烯烃自由基阳离子的取代模式决定了环化模式,当亲核攻击发生在内模式时,这可以设计为通过初始外型亲核环化或桥连双环系统形成稠环系统。