作者:Yuuki Amaoka、Masanori Nagatomo、Mizuki Watanabe、Keisuke Tao、Shin Kamijo、Masayuki Inoue
DOI:10.1039/c4sc01631a
日期:——
The direct alkenylation of C(sp3)âH bonds was achieved by employing benzophenone and 1,2-bis(phenylsulfonyl)ethylene under photo-irradiation conditions. This simple metal-free reaction enables the substitution of heteroatom-substituted methine, methylene and aliphatic C(sp3)âH bonds by (E)-sulfonylalkene units in a highly chemoselective manner. The derived sulfonylalkenes were further converted in a single step to the prenyl derivatives via a second photo-induced radical substitution and to the pyrrole derivatives via cyclization and aromatization steps. The present protocol thus serves as an efficient method for the direct extension of carbon skeletons for the synthesis of structurally complex natural products and pharmaceuticals.
直接将C(sp3)−H键进行烯基化反应,通过在光照射条件下使用苯甲酮和1,2-双(苯磺酰基)乙烯实现。这一简单的无金属反应以高度化学选择性的方式,实现了杂原子取代的次甲基、亚甲基和脂族C(sp3)−H键被(E)-磺酰基烯烃单元的取代。由此衍生的磺酰基烯烃进一步通过第二次光引发的自由基取代反应一步转化为异戊二烯衍生物,或通过环化芳构化步骤转化为吡咯衍生物。因此,本方案成为一种高效的方法,可直接扩展碳骨架,用于合成结构复杂的天然产物和药物。