The Quest for the Ideal Base: Rational Design of a Nickel Precatalyst Enables Mild, Homogeneous C–N Cross-Coupling
作者:Richard Y. Liu、Joseph M. Dennis、Stephen L. Buchwald
DOI:10.1021/jacs.0c00286
日期:2020.3.4
Palladium-catalyzed amination reactions using soluble organic bases have provided a solution to the many issues associated with heterogeneous reaction conditions. Still, homogeneous C-N cross-coupling approaches cannot yet employ bases as weak and economical as trialkylamines. Furthermore, organic base-mediated methods have not been developed for Ni(0/II) catalysis, despite some advantages of such systems
使用可溶性有机碱的钯催化胺化反应为与多相反应条件相关的许多问题提供了解决方案。尽管如此,均相 CN 交叉偶联方法尚不能使用与三烷基胺一样弱且经济的碱。此外,尽管有机碱介导的方法与类似的 Pd 基催化剂相比具有一些优势,但尚未开发出用于 Ni(0/II) 催化的有机碱介导方法。我们设计了一种新的空气稳定且易于制备的 Ni(II) 预催化剂,其带有缺电子的双齿膦配体,能够使用三乙胺 (TEA) 作为碱使芳基三氟甲磺酸酯与芳基胺交叉偶联。该方法可以容忍空间拥挤的偶联伙伴,以及带有碱和亲核试剂敏感官能团的偶联伙伴。借助密度泛函理论 (DFT) 计算,我们确定缺电子辅助配体降低了 Ni 键合胺的 pKa 和从所得 Ni(II)-酰胺络合物还原消除的障碍。此外,我们确定,由于空间因素,排除 Ni 催化剂和碱之间的路易斯酸碱络合对于避免催化剂抑制很重要。
Perfluoroalkanesulfonate esters
申请人:Minnesota Mining and Manufacturing Company
公开号:US04002661A1
公开(公告)日:1977-01-11
Perfluoroalkanesulfonate esters of methylthio-, methylsulfinyl- or methylsulfonyl-substituted phenols. The compounds are herbicides.
氟代烷基磺酸酯甲硫基、甲基亚砜基或甲基磺酰基取代的苯酚。这些化合物是除草剂。
Nickel‐Catalyzed Reductive C−Ge Coupling of Aryl/Alkenyl Electrophiles with Chlorogermanes
作者:Pei‐Feng Su、Ke Wang、Xuejing Peng、Xiaobo Pang、Peng Guo、Xing‐Zhong Shu
DOI:10.1002/anie.202112876
日期:2021.12.13
A new C−Ge bond-forming framework was established, which bridges a gap between a recently developed mild coupling technique and organogermane chemistry. The method provides a mild approach for the synthesis of both aryl and alkenyl germanes, with improved molecular diversity and structural complexity, using readily available carbon electrophiles and chlorogermanes as starting materials.