Palladium-Catalyzed <i>N</i>-Arylation of Sulfoximines with Aryl Sulfonates
作者:Qingjing Yang、Pui Ying Choy、Qingyang Zhao、Man Pan Leung、Hoi Shan Chan、Chau Ming So、Wing-Tak Wong、Fuk Yee Kwong
DOI:10.1021/acs.joc.8b01599
日期:2018.9.21
Palladium-catalyzed C–N bond coupling reaction between NH-sulfoximines and aryl halides (e.g., −Br, −I, and −Cl and pseudohalides −OTf and −ONf) was successfully achieved. Nevertheless, aryltosylates/mesylates left much to be achieved. In this report, a general N-arylation of sulfoximines with aryl sulfonates is described. Using Pd(OAc)2/MeO-CM-phos complex, the N-aryl sulfoximine products can be
Palladium-Catalyzed Miyaura Borylation of Overly Crowded Aryl Chlorides Enabled by a Complementary Localized/Remote Steric Bulk of Ligand Chassis
作者:Man Ho Tse、Rong-Lin Zhong、Fuk Yee Kwong
DOI:10.1021/acscatal.2c00263
日期:2022.3.18
the coupling processes employing highly sterically congested electrophilic partners have been a lasting challenge. Here, we report a general Pd-catalyzed Miyaura borylation of sterically hindered aryl chlorides. The key to the success of this reaction is the distinctive tailor-made phosphine ligand that features a smaller phosphine head and a larger remote steric bulk. This concept is, on the contrary
与使用特权底物的常见交叉偶联反应示例不同,使用高度空间拥挤的亲电伙伴的偶联过程一直是一个持久的挑战。在这里,我们报告了空间受阻芳基氯化物的一般 Pd 催化的 Miyaura 硼化。该反应成功的关键是独特的定制膦配体,其具有更小的膦头和更大的远程空间体积。相反,这一概念与常见膦的现有特性互补,例如 P t -Bu 3、联芳基-PCy 2等,其中它们由位于磷中心的局部空间体积组成。事实上,较小的膦基序有效地允许偶联伙伴在初始阶段接近 Pd 中心。我们的发现表明,即使是高度位阻的 2,6-二异丙基取代的芳基氯也适用于这种开发的催化剂体系。在这些反应条件下观察到良好的官能团相容性,并且对于特定的入口可以实现低至 0.05 mol% Pd 的催化剂负载。这种配体促成的 C-B 键形成的成功被认为为获得适合其他相关的高度空间位阻交叉偶联反应的催化剂建立提供了独特的基础知识。
Montmorillonite Clay Catalyzed Tosylation of Alcohols and Selective Monotosylation of Diols with p-Toluenesulfonic Acid: An Enviro-Economic Route
作者:Boyapati M. Choudary、Naidu S. Chowdari、Mannepalli L. Kantam
DOI:10.1016/s0040-4020(00)00626-8
日期:2000.9
enviro-economic route for tosylation of alcohols and selective monotosylation of diols in good yield directly using p-toluenesulfonic acid together with metal-exchanged montmorillonite instead of p-toluenesulfonyl chloride or p-toluenesulfonic anhydride is described. The Fe3+-montmorillonite clay is the most effective catalyst among metal-exchanged montmorillonites for such tosylation reactions. The activity
描述了直接使用对甲苯磺酸与金属交换的蒙脱石代替对甲苯磺酰氯或对甲苯磺酸酐以高产率直接进行醇的甲苯磺酸化和二醇的选择性单甲苯磺酸酯化的经济经济路线。Fe 3+-蒙脱石粘土是金属交换蒙脱石中对于这种甲苯磺酸化反应最有效的催化剂。活性遵循以下顺序:Fe 3+ > Zn 2+ > Cu 2+ > Al 3+-蒙脱石> K10蒙脱石。可以高纯度实现二醇的区域选择性甲苯磺酸化成单甲苯基化的衍生物。在同时具有伯羟基和仲羟基的二醇中,甲苯磺酰化仅在伯羟基上发生。固体催化剂在环己醇甲苯磺酸化中举例说明的几个循环中显示出一致的活性。
Palladium-Catalyzed Direct Arylation of Polyfluoroarenes for Accessing Tetra-<i>ortho</i>-Substituted Biaryls: Buchwald-type Ligand Having Complementary −PPh<sub>2</sub> Moiety Exhibits Better Efficiency
作者:On Ying Yuen、Man Pan Leung、Chau Ming So、Raymond Wai-Yin Sun、Fuk Yee Kwong
DOI:10.1021/acs.joc.8b01176
日期:2018.8.17
The first general examples of direct C–H arylation of electron-deficient polyfluoroarenes with challenging di-ortho-substituted aryl(heteroaryl) chlorides for tetra-ortho-substituted biaryl synthesis are reported. Key to success is the use of Buchwald-type biaryl phosphine ligand, notably with inexpensive −PPh2 moiety (instead of −PCy2 group). Pd(OAc)2 associated with ligand L9 exhibits even higher