Efficient iridium-catalyzed C-H functionalization/silylation of heteroarenes
Efficient iridium-catalyzed C-H functionalization/silylation of heteroarenes
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DOI：
10.1002/anie.200802456
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发表时间：
2008-01-01
影响因子：
16.6
通讯作者：
Falck, John R.
中科院分区：
文献类型：
--
作者：
Lu, Biao;Falck, John R.
由于其独特的化学、物理和生物学性质，甲硅烷基取代芳烃引起了合成、[1]材料科学[2]和制药部门的广泛兴趣。[3]传统上，甲硅烷基取代基已经通过将芳基锂或镁试剂添加到硅亲电体中来引入，尽管这通常需要使用保护基团。[4]因此，过渡金属催化的芳基卤化物与乙硅烷或氢硅烷的交叉偶联已经越来越流行，特别是如果存在碱敏感或亲核敏感官能团的话。[5]最近，直接CH官能化[6]已经成为芳烃直接甲硅烷基化的概念上和经济上有吸引力的替代方案。然而，很明显，挑战仍然存在，并且该策略的一般效用在许多情况下尤其受到以下因素的限制：（1）差的区域选择性，（2）严格的结构要求，（3）非商业/昂贵的试剂，（4）苛刻的反应条件（通常120-200 ° C），和/或（5）芳烃与硅试剂的不切实际的比率（10：1至60：1）。[7-9]在这里，我们报告了一个有效的，区域选择性的协议联吡啶连接，铱催化的[9] CH官能化/硅烷化的各种杂芳烃在相对温和的条件下。重要的是，该反应不需要保护NH基团，并且仅使用少量过量（3当量）的廉价三乙基硅烷（当量1）。
As a consequence of their unique chemical, physical and biological properties, silylsubstituted arenes have attracted wide interest from the synthetic,[1] material science,[2] and pharmaceutical sectors.[3] Traditionally, silyl substituents have been introduced via addition of aryl lithium or magnesium reagents to silicon electrophiles, although this often necessitates the use of protecting groups.[4] Consequently, transition metal catalyzed cross couplings of aryl halides with disilanes or hydrosilanes have grown in popularity, especially if base-or nucleophile-sensitive functionality are present.[5] More recently, direct CH functionalization [6] has emerged as a conceptually and economically attractive alternative for the direct silylation of arenes. It is evident, however, that challenges remain and the general utility of this strategy is restricted in many instances by, inter alia,(1) poor regioselectivity,(2) stringent structural requirements,(3) noncommercial/expensive reagents,(4) harsh reaction conditions (typically 120–200 C), and/or (5) impractical ratios of arene to silicon reagent (10: 1 to 60: 1).[7–9] Herein, we report an efficient, regioselective protocol for the bipyridine-ligated, iridium-catalyzed [9] CH functionalization/silyation of a wide variety of heteroarenes under comparatively mild conditions. Importantly, the reaction does not require protection of NH groups and uses only a small excess (3 equiv) of inexpensive triethylsilane (eq 1).