Iridium-catalyzed borylation of thiophenes: versatile, synthetic elaboration founded on selective C–H functionalization
作者:Ghayoor A. Chotana、Venkata A. Kallepalli、Robert E. Maleczka、Milton R. Smith
DOI:10.1016/j.tet.2008.02.111
日期:2008.6
various substituted thiophenes to synthesize poly-functionalized thiophenes in good to excellent yields. Apart from common functionalities compatible with iridium-catalyzed borylations, additional functional group tolerance to acyl (COMe), and trimethylsilyl (TMS) groups was also observed. High regioselectivities were observed in borylation of 3-and 2,5-di-substituted thiophenes. Electrophilic aromatic
铱催化的硼酸化反应已应用于各种取代的噻吩以合成多官能化的噻吩,收率非常好。除了与铱催化的硼化反应兼容的常见官能团外,还观察到了对酰基 (COMe) 和三甲基甲硅烷基 (TMS) 基团的额外官能团耐受性。在 3-和 2,5-二取代噻吩的硼酸化中观察到高区域选择性。噻吩硼酸酯上的亲电芳族 CH/C-Si 溴化显示在不破坏 CB 键的情况下发生,并且一锅 CH 硼酸化/Suzuki-Miyaura 交叉偶联已在 2-和 3-硼酸化噻吩上完成。