Competition between addition and redox processes in reactions of Nitroarenes with Lithium-dithianes
作者:Giuseppe Bartoli、Renato Dalpozzo、Loris Grossi、Paolo E. Todesco
DOI:10.1016/0040-4020(86)80023-0
日期:1986.1
The reaction of 2-lithio-1,3-dithianes with nitroarenes gives 2-(or 4-)[(1,3-dithian)-2'-y1]cyclohexa-3,5(or 2,5-)-diene-1-nitronate compounds (conjugate-addition products), free nitroarene radical anions (redox products), 1,3-dithianes and 2,2'-bis-(1,3-dithianes). The conjugate -addition and redox products were converted in the respective nitroaromatic compounds by oxidation in situ with O2 or DDQ
2-lithio-1,3-dithianes与硝基芳烃的反应得到2-(或4-)[(1,3-dithian)-2'-y1]环己-3,5(或2,5-)-二烯-1-硝酸盐化合物(共轭加成产物),游离硝基亚芳基自由基阴离子(氧化还原产物),1,3-二硫烷和2,2'-双-(1,3-二硫烷)。通过用O 2或DDQ原位氧化将共轭加成和氧化还原产物转化为相应的硝基芳族化合物。添加和氧化还原产物之间的比例随着温度的降低而增加。2-H-2-Lithio-1,3-Dithiane既可以提供1,4-和1,6-加成产物,而2-甲基和2-苯基衍生物则只能提供1,6-加成产物。对于这两个自由基物种,提出了一种机制,涉及从二噻吩锂到硝基芳烃的集合,然后是各种衰变途径。