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。
homogeneous palladium catalysts. Better yields were obtained with electron-deficient benzenesulfonylchlorides than with the electron-rich ones. Notably, useful substituents such as bromo or iodo on the benzenesulfonylchloride were tolerated, as no cleavage of the C-Br or C-I bonds was observed under these conditions. The use of Pd/C presents several advantages compared to the previously employed homogeneous
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。
Cross-Coupling Reactions of Aromatic and Heteroaromatic Silanolates with Aromatic and Heteroaromatic Halides
作者:Scott E. Denmark、Russell C. Smith、Wen-Tau T. Chang、Joseck M. Muhuhi
DOI:10.1021/ja8091449
日期:2009.3.4
use of bis(tri-tert-butylphosphine)palladium. Under the optimized conditions, electron-rich, electron-poor, and stericallyhindered arylsilanolates afford cross-coupling products in good yields. Many functional groups are compatible with the coupling conditions such as esters, ketones, acetals, ethers, silyl ethers, and dimethylamino groups. Two particularly challenging substrates, (2-benzofuranyl)dimethylsilanolate
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.
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