通过基于苯并噻唑配体的金属介导的CH键活化,已经制备了几种用于亚胺和喹啉衍生物还原的C,N-螯合环金属化半三明治铱基催化剂。这些铱配合物对各种类型的亚胺的氢化显示出高催化活性。活性最高的催化剂是从甲氧基取代的配合物2获得的,对于还原亚胺6a的催化TOF值为975 h –1。另外,这些半三明治配合物还显示出对N-杂环喹啉衍生物的催化加氢的高效率。对于具有给电子或吸电子基团的各种底物显示出良好的催化活性。配合物1 - 5被完全表征通过NMR,IR和元素分析。通过X射线衍射分析进一步证实了配合物1和4的分子结构。
A novel iridium/acid co-catalyzed transfer hydrogenative C(sp<sup>3</sup>)–H bond alkylation to access functionalized N-heteroaromatics
作者:Zhenda Tan、Huanfeng Jiang、Min Zhang
DOI:10.1039/c6cc03996k
日期:——
A novel iridium/acid co-catalysed transfer hydrogenative coupling strategy, enabling direct alkylation of C(sp3)-H bond and atom-economic access to alkyl chain-lengthened N-Heteroaromatics from six-membered 2-alkyl cyclicamines and aldehydes, has been...
of various nitrogenheterocycles, including but not limited to quinolines, isoquinolines, indoles and pyridinium salts, in an aqueous solution of HCO2H/HCO2Na under mild conditions. The catalyst shows excellent functional‐group compatibility and high turnover number (up to 7500), with catalyst loadings as low as 0.01 mol % being feasible. Mechanistic investigation of the quinolinereduction suggests
在温和条件下,显示出环金属化的铱络合物在HCO 2 H / HCO 2 Na的水溶液中催化各种氮杂环的转移加氢反应,包括但不限于喹啉,异喹啉,吲哚和吡啶鎓盐。该催化剂表现出出色的官能团相容性和高周转率(最高7500),催化剂用量低至0.01 mol%是可行的。对喹啉还原反应的机理研究表明,转移氢化反应是通过1,2和1,4加成途径进行的,催化转化受氢化物转移步骤的限制。
Regioselective Acceptorless Dehydrogenative Coupling of N-Heterocycles toward Functionalized Quinolines, Phenanthrolines, and Indoles
been developed for the oxidant‐ and base‐free dehydrogenativecoupling of N‐heterocycles at mild conditions. Under the action of an iridium catalyst, N‐heterocycles undergo multiple sp3 CH activation steps, generating a nucleophilic enamine that reacts in situ with various electrophiles to give highly functionalized products. The dehydrogenativecoupling can be cascaded with Friedel–Crafts addition