Direct Selective Oxidative Cross-Coupling of Simple Alkanes with Heteroarenes
作者:Andrey P. Antonchick、Lars Burgmann
DOI:10.1002/anie.201209584
日期:2013.3.11
A dream reaction: An efficient and practical method for the oxidative cross‐coupling of heteroaromatic compounds and simplealkanes has been developed. The desired products are smoothly and regioselectively formed under mild reaction conditions at ambient temperature in a hypervalent‐iodine‐mediated transformation. The method allows for preferential transformation of stronger CH bonds in the presence
hydroboration with catecholborane), alkyl iodides (via iodineatom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle and no external oxidant is required. A rateconstant for the addition of a primary radical to N-methoxylepidinium >107 M−1 s−1 was experimentally determined. This rateconstant is more than one order of magnitude
报道了N-甲氧基吡啶鎓盐与由烯烃(通过与儿茶酚硼烷的硼氢化反应)、烷基碘化物(通过碘原子转移)和黄原酸盐产生的烷基自由基的单烷基化反应。反应在中性条件下进行,因为不需要酸来活化杂环,也不需要外部氧化剂。将伯自由基添加到N-甲氧基吡啶鎓的速率常数>10 7 M -1 s -1是通过实验确定的。该速率常数比将伯烷基自由基添加到质子化来比啶所测得的速率常数大一个数量级以上,这表明甲氧基吡啶鎓盐对自由基具有显着的反应性。该反应已用于制备独特的吡啶化萜类化合物,并扩展到富电子烯烃(包括烯醇酯、烯醇醚和烯酰胺)的三组分碳吡啶基化反应。