Catalytic Direct Dehydrogenative Cross-Couplings of C–H (Pro)Nucleophiles and Allylic Alcohols without an Additional Oxidant
Catalytic Direct Dehydrogenative Cross-Couplings of C–H (Pro)Nucleophiles and Allylic Alcohols without an Additional Oxidant
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DOI：
10.1021/cs501495g
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发表时间：
2015-01
期刊：
影响因子：
12.9
通讯作者：
Marcel Weiss;R. Peters
中科院分区：
文献类型：
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作者：
Marcel Weiss;R. Peters
sp2杂化C原子之间的过渡金属催化的交叉偶联反应在目标和多样性导向的合成中至关重要。理想的交叉偶联反应既不需要任何离去基团，也不需要化学计量试剂。在本文中，我们报道了芳香族 C-H 键（在大多数情况下使用吲哚底物）和烯丙醇之间的首次直接脱氢交叉偶联，不需要额外的经典化学计量氧化剂并提供 β-芳基酮作为增值产品。人们发现基于钌茂或二茂铁的双金属环，其中 Pd(II) 或 Pt(II) 是催化活性中心，是特别有效的催化剂。对照实验表明，双金属环最初将烯丙醇转化为乙烯基酮，然后在催化剂存在下将芳香族底物烷基化。事实证明，脱氢偶联不需要经典的化学计量氧化剂...
Transition-metal-catalyzed cross-coupling reactions between sp2-hybridized C atoms are of prime importance in both target and diversity oriented synthesis. Ideal cross-coupling reactions would neither require any leaving groups nor stoichiometric reagents. In this article, we report the first direct dehydrogenative cross-couplings between aromatic C–H bonds (in most cases using indole substrates) and allylic alcohols, which do not require an additional classical stoichiometric oxidizing agent and provide β-arylketones as value-added products. Ruthenocene- or ferrocene-based bismetallacycles, in which either Pd(II) or Pt(II) are the catalytically active centers, were found to be particularly efficient catalysts. Control experiments suggest that the bismetallacycles initially transform the allylic alcohols into vinylketones, which then alkylate the aromatic substrate in the presence of the catalyst. The fact that the dehydrogenative coupling does not require a classical stoichiometric oxidizing agent is exp...