Palladium-Catalyzed Oxidative C-H/C-H Cross-Coupling of Indoles and Pyrroles with Heteroarenes
Palladium-Catalyzed Oxidative C-H/C-H Cross-Coupling of Indoles and Pyrroles with Heteroarenes
复制标题
钯催化吲哚和吡咯与杂芳烃的氧化 C-H/C-H 交叉偶联
DOI：
10.1002/anie.201101416
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发表时间：
2011-01-01
影响因子：
16.6
通讯作者：
You, Jingsong
中科院分区：
文献类型：
--
作者：
Wang, Zhen;Li, Kaizhi;You, Jingsong
双杂芳基结构模体广泛存在于聚合物、先进材料、液晶、配体、医药分子和天然产物中。[1]过渡金属催化的杂芳基卤化物或替代物与杂芳基金属的交叉偶联反应是制备双杂芳基化合物最有效和最可靠的方法之一。[2]然而，从合成简单性、原子经济性和可持续化学的角度来看，通过双C？H活化杂芳烃之间的直接氧化偶联将是连接两个杂芳烃的最理想的策略，从而避免在偶联反应之前两个底物的预官能化。几个小组公开了他们的开创性工作，针对过渡金属催化的含直接基芳烃和芳烃之间的氧化C？H/C±H交叉偶联，两个简单芳烃之间的交叉偶联[4]，[5]以及杂芳烃和芳烃之间的交叉偶联。可以说，这一领域的剩余挑战是为各种杂芳烃开发一种相容的方法，因为这些物种经常被证明经历了同源偶联，并且参与偶联过程的稳定性不够。此外，杂芳烃的存在可能会导致偶联反应的反应活性和选择性降低，因为底物和产物中的杂原子都与金属络合物结合。最近，我们首次报道了Pd-(OAc)2催化的铜盐激活的黄嘌呤、氮唑和吡啶N-氧化物与噻吩类和呋喃类化合物的氧化C？H/C？H交叉偶联反应。[8]最近，Ofial和他的同事描述了苯并噻唑和苯并咪唑与N-、O-和S含唑的高效钯催化脱氢交叉偶联反应。[9](杂)芳基吲哚和吡咯是医药、香料、染料、农用化学品、原料和天然产物的重要结构元素(方案1)。过渡金属催化的直接氧化C？H/C？H偶联方法生成(杂化)芳基吲哚和吡咯是一个巨大的合成挑战，因为吲哚和吡咯
The bi-heteroaryl structural motif is prevalent in polymers, advanced materials, liquid crystals, ligands, molecules of medicinal interest, and natural products.[1] Transition-metalcatalyzed cross-coupling reactions of a heteroaryl halide or surrogate with a heteroaryl metal represents one of the most powerful and reliable methodologies for the preparation of bi-heteroaryl compounds.[2] However, from the viewpoint of synthetic simplicity, atom economy, and sustainable chemistry, direct oxidative coupling between heteroarenes through a double CÀH activation would be the most ideal strategy for connecting two heteroarenes, thus avoiding prefunctionalization of both of substrates prior to the coupling reaction.[3] In recent years, a few groups disclosed their pioneering work directed toward transition-metal-catalyzed oxidative CÀH/CÀH cross-coupling between a directing-group-containing arene and an arene,[4] between two simple arenes,[5] and between a heteroarene and an arene.[6, 7] In sharp contrast, metal-catalyzed direct oxidative CÀC couplings between two heteroarenes have a limited substrate scope. Arguably the remaining challenge in this area is to develop a compatible method for a variety of heteroarenes since such species have often been documented to undergo homocoupling, and have inadequate stability for participating in the coupling process. In addition, the presence of heteroarenes may lead to low reactivity and selectivity in coupling reactions because of the binding of the heteroatom in both the substrate and product to the metal complex. Recently, we reported the first Pd-(OAc) 2-catalyzed copper-salt-activated oxidative CÀH/CÀH cross-coupling of xanthines, azoles, and pyridine N-oxides with thiophenes and furans.[8] Quite recently, Ofial and coworkers described the efficient palladium-catalyzed dehydrogenative cross-couplings of benzothiazole and benzimidazoles with N-, O-, and S-containing azoles.[9](Hetero) arylated indoles and pyrroles represent important structural elements for pharmaceuticals, fragrances, dyes, agrochemicals, materials, and natural products (Scheme 1). Transition-metal-catalyzed direct oxidative CÀH/CÀH coupling methods to form (hetero) arylated indoles and pyrroles pose a great synthetic challenge because the indole and