首次成功开发了一种基于廉价过渡金属镍的高效催化体系,用于挑战性环状烯基砜,3-取代的苯并[ b ]噻吩1,1-二氧化物的不对称加氢。以高收率(95-99%)和优异的对映选择性(90-99%ee)获得了一系列氢化产物,手性2,3-二氢苯并[ b ]噻吩1,1-二氧化物。根据非线性效应研究,氘标记实验和DFT计算研究的结果,为这种镍催化的不对称氢化提供了合理的催化机理,表明该氢化产物中两个加成的氢原子可能来自H 2。 通过插入Ni–H和随后的氢解反应。
Completely Regioselective Direct C–H Functionalization of Benzo[b]thiophenes Using a Simple Heterogeneous Catalyst
摘要:
The first completely selective C3 C-H arylation of benzo[b]thiophenes is reported, demonstrating previously unexploited reactivity of palladium. Benzo[b]thiophenes are coupled with readily available aryl chlorides using a ligand-free, dual catalytic system of heterogeneous Pd/C and CuCl. The reaction is operationally simple and insensitive to air and moisture, and it provides valuable products with complete selectivity. Significant investigations into the nature of the active catalytic species and mechanistic considerations are discussed.
The first example of a regioselective β-arylation of benzo[b]thiophenes and thiophenes at room temperature with aryl iodides as coupling partners is reported. This methodology stands out for its operational simplicity: no prefunctionalization of either starting material is required, the reaction is insensitive to air and moisture, and it proceeds at room temperature. The mild conditions afford wide
报道了苯并[b]噻吩和噻吩在室温下以芳基碘作为偶联伙伴的区域选择性β-芳基化的第一个例子。这种方法因其操作简单而突出:不需要任何一种起始材料的预官能化,反应对空气和水分不敏感,并且在室温下进行。温和的条件提供了广泛的官能团耐受性,通常具有完全的区域选择性和高产率,从而形成高效的催化系统。包括 13C 和 2H KIE 在内的初步机理研究表明,该过程是通过噻吩双键上的协同碳钯化作用发生的,然后是碱基辅助的抗消除作用。
Double C-H Functionalization to Construct Polycyclic Heteroarenes Catalyzed by an Ionic Salt of a Pd Complex with an N-Heterocyclic Carbene Ligand
作者:Sanjay Kumar Ghosh、Bing-Chiuan Kuo、Hsiang-Yu Chen、Jia-Ying Li、Shuang-De Liu、Hon Man Lee
DOI:10.1002/ejoc.201500417
日期:2015.7
A new ionicsalt, cis-[Pd(L)(PPh3)(H2O)2](SO3CF3)2 (A), in which L is an amido-functionalized N-heterocycliccarbene (NHC) ligand, has been prepared by the salt metathesis reaction between [Pd(L)(PPh3)Cl2] and AgOTf in wet acetonitrile. It was successfully characterized by NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction analysis. Complex A was found to be effective in catalyzing
一种新的离子盐,顺式-[Pd(L)(PPh3)(H2O)2](SO3CF3)2 (A),其中 L 是酰胺基官能化的 N-杂环卡宾 (NHC) 配体,由[Pd(L)(PPh3)Cl2] 和 AgOTf 在湿乙腈中的盐复分解反应。通过核磁共振谱、元素分析和单晶X射线衍射分析成功地对其进行了表征。发现配合物 A 在 Cu(OAc)2 和四正丁基溴化铵的存在下,可有效催化各种含氮和硫杂芳烃的双 C-H 官能化,以与炔烃形成稠合的多环杂芳烃化合物。吲哚、噻吩、咪唑并[1,2-a] 吡啶和咪唑用作底物。特别是,在所采用的条件下,可以获得有趣的咪唑并[5,1,2-cd]吲哚嗪化合物。
Pd-Catalyzed β-Selective Direct C–H Bond Arylation of Thiophenes with Aryltrimethylsilanes
作者:Kenji Funaki、Tetsuo Sato、Shuichi Oi
DOI:10.1021/ol3029109
日期:2012.12.21
Direct arylation of thiophenes and benzothiophenes with aryltrimethylsilanes was effectively catalyzed by PdCl2(MeCN)2 in the presence of CuCl2 as an oxidant. The reaction preferentially occurred at the β-position of both thiophenes and benzothiophenes.
first example of near-room-temperature α-arylation of benzo[b]thiophenes is reported. The discovery rests on the observation of a switch in α-/β-regioselectivity at different loadings of Pd2(dba)3·CHCl3 in the coupling between benzo[b]thiophene and 4-iodotoluene. We show that this unprecedented regioselectivity switch is driven by a Ag(I)-mediated C–H activation at the α-C–H position, which becomes the
Iridium-Catalyzed Asymmetric Hydrogenation of Benzo[<i>b</i>
]thiophene 1,1-Dioxides
作者:Paolo Tosatti、Andreas Pfaltz
DOI:10.1002/anie.201701409
日期:2017.4.10
An efficient iridium‐catalyzed asymmetrichydrogenation of substituted benzothiophene 1,1‐dioxides is described. The use of iridium complexes with chiral pyridyl phosphinite ligands provides access to highly enantiomerically enriched sulfones with substituents at the 2‐ and 3‐position. Sulfones of this type are of interest as core structures of agrochemicals and pharmaceuticals. Moreover, they can