Competition between nucleophilic addition and electron-transfer process in the reaction of 9-diazo-10-anthrone with grignard reagents
作者:Paolo Bruni、Patricia Carloni、Carla Conti、Elisabetta Giorgini、Lucedio Greci、Marco Iacussi、Pierluigi Stipa、Giorgio Tosi
DOI:10.1016/0040-4020(96)00291-8
日期:1996.5
decrease as the oxidation potentials (Eox) of the Grignards decrease: at the same time additional compounds, formed through a radical mechanism, are obtained in higher yields. The reaction has been interpreted as a competition between single electron transfer (SET) and nucleophilic attack, which occur with ratios varying with the oxidation potentials of the Grignard reagents E'vidences for the SET pathway
9-重氮-10-蒽酮与RMgX(R = Me,Et,Bu n,5-己烯基,Pr i,苄基,Bu t)反应,基本生成9-烷基偶氮-10-羟基衍生物,将其分离为互变异构醌结构为9,10-蒽醌的烷基hydr。这些化合物的收率随着氧化电位的降低而降低(E ox)的格利雅(Grignards)含量降低:同时,通过自由基机理形成的其他化合物也得到了更高的收率。该反应已被解释为单电子转移(SET)与亲核攻击之间的竞争,这种竞争的比例随格氏试剂的氧化电势而变化。E'的证据表明,SET途径的存在是在存在2的条件下进行的实验,2,6,6-四甲基哌啶-1-氧基(TEMPO)作为C中心自由基的清除剂。