Palladium‐Catalyzed Methylation of Nitroarenes with Methanol
作者:Lin Wang、Helfried Neumann、Matthias Beller
DOI:10.1002/anie.201814146
日期:2019.4.8
procedure for the synthesis of N‐methyl‐arylamines directly from nitroarenes using methanol as green methylating agent was developed. The key to success is the use of a specific catalyst system consisting of palladium acetate and the ligand 1‐[2,6‐bis(isopropyl)phenyl]‐2‐[tert‐butyl(2‐pyridinyl)phosphino]‐1H‐Imidazole (L1). The generality of this protocol is demonstrated in the synthesis of more than 20
作者:Shire Elmi、Per Heggen、Bjarte Holmelid、Didrik Malthe-Sørensen、Leiv K. Sydnes
DOI:10.1080/00304948.2016.1206425
日期:2016.9.2
conditions 2a was not formed at all and a complex product mixture was obtained from which the only reasonably pure product isolated in low yield (4%) was 2,20,4,40-tetramethylazobenzene (3a). The iodination of benzene derivatives is influenced by the nature of the substituents. It was therefore of interest to investigate the reaction of some activated and deactivated aniline derivatives under the conditions
A rhodium-catalyzed annulative reaction between azobenzenes and nitrosoarenes has been developed, leading to a series of phenazines in moderate to good yields. This procedure proceeds with sequential chelation-assisted addition of aryl C–H to nitrosoarenes and ring closure by electrophilic attack of azo group to aryl. During this transformation, the azo group served as not only a traceless directing
Bi(I)-Catalyzed Transfer-Hydrogenation with Ammonia-Borane
作者:Feng Wang、Oriol Planas、Josep Cornella
DOI:10.1021/jacs.9b00594
日期:2019.3.13
transfer-hydrogenation utilizing a well-defined Bi(I) complex as catalyst and ammonia-borane as transfer agent has been developed. This transformation represents a unique example of low-valent pnictogen catalysis cycling between oxidation states I and III, and proved useful for the hydrogenation of azoarenes and the partial reduction of nitroarenes. Interestingly, the bismuthinidene catalyst performs
已经开发了利用明确定义的 Bi(I) 配合物作为催化剂和氨硼烷作为转移剂的催化转移氢化。这种转变代表了氧化态 I 和 III 之间的低价色素原催化循环的独特例子,并被证明可用于偶氮芳烃的氢化和硝基芳烃的部分还原。有趣的是,铋烯催化剂在低价过渡金属敏感官能团的存在下表现良好,并且与类似的磷基催化相比表现出正交反应性。机理研究表明,一种难以捉摸的铋物种的中间体,被认为是氢化和氢形成的原因。
Transition Metal-Free Oxidative Coupling of Primary Amines in Polyethylene Glycol at Room Temperature: Synthesis of Imines, Azobenzenes, Benzothiazoles, and Disulfides
作者:Abhinandan D. Hudwekar、Praveen K. Verma、Jaspreet Kour、Shilpi Balgotra、Sanghapal D. Sawant
DOI:10.1002/ejoc.201801610
日期:2019.2.14
A transition metal‐free protocol has been developed for the oxidativecoupling of primary amines to imines and azobenzenes, thiols to disulfides, and 2‐aminothiophenols to benzothiazoles, offering excellent yields. The advantageous features of the present environmentally benign methodology include the usage of biocompatable and green reaction conditions such as solvent, room temperature reactions,