Theoretical investigation of the reaction of dialkylzincs with α-alkoxycarbonyl radicals. Evaluation of α-bromoacrylates as radical acceptors in radical-polar crossover processes
作者:François Vibert、Julien Maury、Hugo Lingua、Eric Besson、Didier Siri、Michèle P. Bertrand、Laurence Feray
DOI:10.1016/j.tet.2015.09.045
日期:2015.11
The evaluation of ethyl α-bromoacrylate as radical acceptor in dialkylzinc radical-polar cascades addresses the question of the parameters controlling homolytic substitution at zinc by α-alcoxycarbonyl radicals. Under non-degassed medium ethyl α-bromoacrylate reacts with diethylzinc to give a bromocyclopropane. The reaction involves successively radical addition, SH2 at zinc, conjugate addition of
乙基α-bromoacrylate作为自由基受体的二烷基锌中自由基极性级联地址评估所述参数控制在锌通过α-alcoxycarbonyl自由基均裂取代的问题。下与二乙基锌非脱气介质乙基α-bromoacrylate发生反应,得到溴环丙烷。该反应涉及依次基加,S ħ 2在锌,共轭加成所得的烯醇化物与亲电基片和环闭合。理论计算进行以获得更好的洞察详细机制。他们突出锌(II)的螯合的上正式S上的冲击ħ 2步骤。讨论了在其他亲电子试剂(醛和酰基硅烷)存在下进行的其他实验。