Efficient Pd-Catalyzed Direct Arylations of Heterocycles with Unreactive and Hindered Aryl Chlorides
摘要:
A highly electron-rich Pd complex can efficiently catalyze the direct arylation of heteroaromatics with unreactive and sterically congested aryl chlorides.
Palladium-catalyzed direct arylation polymerization (DArP) has recently attracted much attention as a simple and easy means of synthesizing π-conjugated polymers. We have reported a novel catalytic system for DArP. While the already known catalytic systems for direct arylation commonly require the use of a highly polar solvent such as DMA, our system is sufficiently reactive in less polar THF and toluene
作为合成π-共轭聚合物的简单方法,钯催化的直接芳基化聚合(DArP)最近引起了广泛的关注。我们已经报道了一种新型的DArP催化系统。虽然已知的直接芳基化催化系统通常需要使用高极性溶剂(例如DMA),但我们的系统在极性较低的THF和甲苯中具有足够的反应性。这种独特的催化性能的关键是使用具有o -MeO取代基作为支撑配体的P(2-MeOC 6 H 4)3(L1)。在本文中,我们通过假定的催化中间体的分离研究了L1的作用。芳基乙酸钯络合物[PdAr(OAc)(L1)] n(Ar = Ph(1a),2,6-Me 2 C 6 H 3(5b))通过在存在下将ArBr氧化添加到[Pd P(o- tolyl)3 } 2 ]中来制备的L1,接着用AgOAc阴离子配位体交换。X射线衍射分析表明,图1A是一个二聚化合物(Ñ = 2)桥接由两种类型的μ-OAC配体,而图5B是一个单体物质(Ñ = 1)PO-螯合配位L1(L1
Factors Controlling the Reactivity of Heteroarenes in Direct Arylation with Arylpalladium Acetate Complexes
The palladium-catalyzed direct arylation of heteroarenes with aryl halides has emerged as a viable alternative to conventional cross-coupling reactions. This paper reports a detailed mechanistic study on factors controlling the reactivity of heteroarenes in direct arylation with well-defined models of the presumed intermediate [PdAr(O2CMe-κ2O)L] (1). Although recent theoretical studies have provided
Effects of PAr<sub>3</sub> Ligands on Direct Arylation of Heteroarenes with Isolated [Pd(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)(μ-O<sub>2</sub>CMe)(PAr<sub>3</sub>)]<sub>4</sub> Complexes
The palladium-catalyzed direct arylation of heteroarenes with aryl halides has attracted considerable attention as a simple cross-couplingprocess that does not need organometallic reagents. It is generally accepted that this catalysis proceeds via an arylpalladium carboxylate intermediate, which produces direct arylation products via the sequence of three elementary processes: (a) substrate coordination
钯催化的杂芳烃与芳基卤化物的直接芳基化作为一种不需要有机金属试剂的简单交叉偶联方法已引起了广泛的关注。通常认为,这种催化作用是通过芳基钯羧酸盐中间体进行的,该中间体通过以下三个基本过程的序列产生直接的芳基化产物:(a)底物配位,(b)C–H键断裂和(c)C–C还原消除。本文描述了动力学调查四种PAR的效果3点使用分离的复合物上直接芳基化的配体[将Pd(2,6-ME 2 ç 6 ħ 3)(μ-O 2 CME)(PAR 3)] 4(1个:Ar = Ph(a),4-MeOC 6 H 4(b),4-FC 6 H 4(c),4-F 3 CC 6 H 4(d))。虽然图1A - ð具有在固态的四聚体结构,它们是处于快速平衡与单体物种[钯(2,6--ME 2 ç 6 ħ 3)(O 2 CME-κ 2 ö)(PAR 3)]在解决方案中。配合物1a – d与2-甲基噻吩(3)和苯并噻唑(4)的THF溶液
Efficient Pd-Catalyzed Direct Arylations of Heterocycles with Unreactive and Hindered Aryl Chlorides
作者:Debalina Ghosh、Hon Man Lee
DOI:10.1021/ol302635e
日期:2012.11.2
A highly electron-rich Pd complex can efficiently catalyze the direct arylation of heteroaromatics with unreactive and sterically congested aryl chlorides.