已开发出由铱-二氟配合物催化的各种2-烷基和2-芳基取代的喹喔啉衍生物的一般不对称氢化反应。在温和的反应条件下,可以以高收率和高达95%的良好至优异的对映选择性获得相应的生物学上相关的2-取代-1,2,3,4-四氢喹喔啉单元。催化剂比为S / C = 1000且以克为单位,Ir-二氟膦配合物的催化活性得以保持,并显示出其潜在价值。最后,我们证明了我们的方法在化合物(S)-9的合成中的应用,该化合物是胆固醇酯转移蛋白(CETP)的抑制剂。
Safe and Reliable Synthesis of Diazoketones and Quinoxalines in a Continuous Flow Reactor
摘要:
A flow method for the synthesis of aliphatic and aromatic diazoketones from acyl chloride precursors has been developed and used to prepare quinoxalines in a multistep sequence without isolation of the potentially explosive diazoketone. The protocol showcases an efficient in-line purification using supported scavengers with time-saving and safety benefits and in particular a reduction in the operator's exposure to carcinogenic phenylenediamines.
The first Fe-catalysed alkylation of 2-methyl and 4-methyl-azaarenes with a series of alkyl and hetero-aryl alcohols is reported (>39 examples and up to 95% yield). Multi-functionalisation of pyrazines and synthesis of anti-malarial drug (±) Angustureine significantly broaden the scope of this methodology. Preliminary mechanistic investigation, deuterium labeling and kinetic experiments including trapping
Cobalt-catalyzed alkylation of methyl-substituted N-heteroarenes with primary alcohols: direct access to functionalized N-heteroaromatics
作者:Anju Mishra、Ambikesh D. Dwivedi、Sujan Shee、Sabuj Kundu
DOI:10.1039/c9cc08448g
日期:——
Phosphine free, air and moisture stable Co(NNN) complex catalyzed alkylation of various methyl-substituted N-heteroarenes with alcohols is reported. Following the borrowing hydrogen methodology, a variety of methyl-substituted N-heteroarenes can be functionalized efficiently. To understand the mechanism of this reaction various kinetic and control experiments were carried out.
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...
Nickel-Catalyzed Dehydrogenation of N-Heterocycles Using Molecular Oxygen
作者:Sourajit Bera、Atanu Bera、Debasis Banerjee
DOI:10.1021/acs.orglett.0c02271
日期:2020.8.21
Herein, an efficient and selective nickel-catalyzed dehydrogenation of five- and six-membered N-heterocycles is presented. The transformation occurs in the presence of alkyl, alkoxy, chloro, free hydroxyl and primary amine, internal and terminal olefin, trifluoromethyl, and ester functional groups. Synthesis of an important ligand and the antimalarial drug quinine is demonstrated. Mechanistic studies