Rh(III)-catalyzed [4 + 1]-annulation of azobenzenes with α- carbonyl sulfoxonium ylides toward 3-acyl-(2H)-indazoles
作者:Jiawei Zhu、Song Sun、Jiang Cheng
DOI:10.1016/j.tetlet.2018.05.001
日期:2018.6
A Rh(III)-catalyzed [4 + 1]-annulation of azobenzenes with α- carbonylsulfoxoniumylides was developed to access 2H-indazoles in moderate to excellent yields with good functional group compatibilities. It proceeded with the sequential insertion of the Rh(III) carbene to the C−H bond and cyclization steps, where sulfoxoniumylides served as efficient and stable carbene precursor.
Rh(III)-catalyzed annulation of azobenzenes and α-Cl ketones toward 3-acyl-2H-indazoles
作者:Huan Li、Yuxuan Han、Zi Yang、Zhenyu Yao、Lianhui Wang、Xiuling Cui
DOI:10.1016/j.cclet.2020.12.027
日期:2021.5
afforded in up to 97% yields for more than 30 examples. The obtained products are potentiallyvaluable in organic synthesis and drug discovery. This protocol featured with high efficiency, extensive functional group tolerance and mild reaction conditions. The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.
Direct Acyl Radical Addition to 2<i>H</i>-Indazoles Using Ag-Catalyzed Decarboxylative Cross-Coupling of α-Keto Acids
作者:Ganganna Bogonda、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.8b00920
日期:2018.5.4
A direct acyl radical addition to 2H-indazoles has been achieved for the first time, where the less-aromatic quinonoid 2H-indazoles readily accepted radical species to the C-3 position. Motivated by the lack of direct acylation strategy for 2H-indazoles, the current method utilizes the radical acceptability of 2H-indazoles, discovering an ambient temperature reaction to provide facile access to a diverse
Synthesis of (2<i>H</i>)-Indazoles through Rh(III)-Catalyzed Annulation Reaction of Azobenzenes with Sulfoxonium Ylides
作者:Hyunjung Oh、Sangil Han、Ashok Kumar Pandey、Sang Hoon Han、Neeraj Kumar Mishra、Saegun Kim、Rina Chun、Hyung Sik Kim、Jihye Park、In Su Kim
DOI:10.1021/acs.joc.8b00501
日期:2018.4.6
The rhodium(III)-catalyzed C–H functionalization followed by intramolecular annulation reactions between azobenzenes and sulfoxonium ylides is described. This protocol leads to the efficient formation of 3-acyl (2H)-indazoles with a range of substrate scope. A high level of chemoselectivity and functional group tolerance of this transformation were also observed.
Oxidative cross-dehydrogenative coupling (CDC) <i>via</i> C<sub>(sp2)</sub>–H bond functionalization: <i>tert</i>-butyl peroxybenzoate (TBPB)-promoted regioselective direct C-3 acylation/benzoylation of 2<i>H</i>-indazoles with aldehydes/benzyl alcohols/styrenes
proceeds via the addition of an in situ generated acyl radical (from aldehydes/benzyl alcohols/styrenes) on 2H-indazoles. The functional group tolerance, broad substrate scope, control/competitive experiments and gram-scale synthesis and its application to the synthesis of anti-inflammatory agent 11 and novel indazole-fused diazepine 13 further signify the versatile nature of the developed methodology