Palladium- and copper-catalyzed arylation of carbon-hydrogen bonds.
Palladium- and copper-catalyzed arylation of carbon-hydrogen bonds.
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DOI：
10.1021/ar9000058
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发表时间：
2009-08-18
影响因子：
18.3
通讯作者：
Shabashov D
中科院分区：
文献类型：
--
作者：
Daugulis O;Do HQ;Shabashov D
过渡金属催化的C-H键官能化是生成碳-碳键的有效方法。虽然在过去十年中，这一领域取得了重大进展，但仍然存在许多挑战。首先，大多数方法都是底物特异性的，因此不能推广。其次，未活化的（即不是苄基或α-杂原子）sp3 C-H键转化为C-C键是罕见的，大多数实例限于叔丁基基团-这种转化本质上是简单的，因为没有可以消除的β-氢。最后，通常用于将C-H键转化为C-C键的钯、铑和钌催化剂是昂贵的。催化活性较低的金属（如铜、铁和锰）很少使用。本报告介绍了我们为解决这三个问题所作的努力。我们发展了一种用碘代芳烃直接进行含基团芳烃芳基化反应的通用方法。以乙酸钯为催化剂，在几乎相同的条件下，对苯胺、苯甲酰胺、苯甲酸、苄胺和2-取代吡啶衍生物进行了芳基化反应。我们还开发了一种钯催化的芳基辅助的未活化的sp3 C-H键的芳基化反应的方法。该程序允许羧酸衍生物的β-芳基化和胺衍生物的γ-芳基化。此外，铜催化可用于介导酸性芳烃C-H键（即在DMSO中pKa值<35的那些）的芳基化。使用碘化铜催化剂与碱和菲咯啉配体的组合，我们成功地芳基化富电子和缺电子杂环和贫电子芳烃具有至少两个吸电子基团。该反应表现出不寻常的区域选择性：芳基化发生在最受阻的位置。这种铜催化的方法补充了众所周知的C-H活化/硼基化方法，其中官能化通常发生在最少受阻的位置。我们还描述了初步调查，以确定这些转变的机制。我们预计，其他过渡金属，包括铁，镍，钴，和银，也将能够促进去质子化/芳基化反应序列。
The transition-metal-catalyzed functionalization of C-H bonds is a powerful method for generating carbon-carbon bonds. Although significant advances to this field have been reported during the last decade, many challenges remain. First, most of the methods are substrate-specific and thus cannot be generalized. Second, conversions of unactivated (i.e. not benzylic or alpha to heteroatom) sp3 C–H bonds to C–C bonds are rare, with most examples limited to t-butyl groups—a conversion that is inherently simple because there are no β-hydrogens that can be eliminated. Finally, the palladium, rhodium, and ruthenium catalysts routinely used for the conversion of C–H bonds to C–C bonds are expensive. Catalytically active metals that are cheaper and less exotic (e.g. copper, iron, and manganese) are rarely used. This Account describes our attempts to provide solutions to these three problems. We have developed a general method for directing-group-containing arene arylation by aryl iodides. Using palladium acetate as the catalyst, we arylated anilides, benzamides, benzoic acids, benzylamines, and 2-substituted pyridine derivatives under nearly identical conditions. We have also developed a method for the palladium-catalyzed auxiliary-assisted arylation of unactivated sp3 C–H bonds. This procedure allows for the β-arylation of carboxylic acid derivatives and the γ-arylation of amine derivatives. Furthermore, copper catalysis can be used to mediate the arylation of acidic arene C–H bonds (i.e. those with pKa values <35 in DMSO). Using a copper iodide catalyst in combination with a base and a phenanthroline ligand, we successfully arylated electron-rich and electron-deficient heterocycles and electron-poor arenes possessing at least two electron-withdrawing groups. The reaction exhibits unusual regioselectivity: arylation occurs at the most hindered position. This copper-catalyzed method supplements the well-known C–H activation/borylation methodology, in which functionalization usually occurs at the least hindered position. We also describe preliminary investigations to determine the mechanisms of these transformations. We anticipate that other transition metals, including iron, nickel, cobalt, and silver, will also be able to facilitate deprotonation/arylation reaction sequences.
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影响因子：
15
作者：
Desai, Lopa V.;Stowers, Kara J.;Sanford, Melanie S.
通讯作者：
Sanford, Melanie S.
影响因子：
16.6
作者：
Bedford, RB;Coles, SJ;Limmert, ME
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影响因子：
15
作者：
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影响因子：
2.8
作者：
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通讯作者：
Ferraccioli, Raffaella
影响因子：
5.2
作者：
Campeau, LC;Thansandote, P;Fagnou, K
通讯作者：
Fagnou, K