Electro-organic reactions. Part 46. Diels-Alder trapping of o-quinodimethane generated by redox-mediated cathodic reduction of α,α′-dibromo-o-xylene in the presence of hindered dienophiles
作者:Erada Oguntoye (neéEru)、Sabine Szunerits、James H.P Utley、Peter B Wyatt
DOI:10.1016/s0040-4020(96)00345-6
日期:1996.5
Hindered, electron-deficient alkenes 5–11 have been prepared, including analogues of maleic anhydride, N-phenylmaleimide and benzoquinone. Cyclic voltammetry showed that most of these compounds can undergo reduction to form relatively persistent radical-anions, which can mediate the reductive cleavage of α,α′-dibromo-o-xylene. Preparative electrolytic reduction of α,α′-dibromo-o-xylene was performed
已制备了受阻的电子不足的烯烃5-11,包括马来酸酐,N-苯基马来酰亚胺和苯醌的类似物。循环伏安法表明,这些化合物中的大多数都可以还原形成相对持久的自由基阴离子,这些自由基可以介导α,α'-二溴-邻二甲苯的还原裂解。在烯烃5-11的存在下进行制备性电解还原α,α'-二溴-邻二甲苯。在某些情况下,烯烃和邻位的Diels-Alder加合物可以分离出喹啉二甲烷,从亲二烯体5a,5b和6a获得特别高产率的环加合物。