hetero-Diels-Alder reaction (Povarov reaction) and hydrogen-transfer process. The reaction of electron-richolefins and excess amount of imines in the presence of acid catalysts under appropriate conditions affords substituted quinolines in a single operation. In the cascade process, the catalysts, such as Tf2NH, TfOH, and Lewis acids, catalyze two mechanistically distinct reactions (auto-tandem catalysis)
Mo(VI)-catalyzed Synthesis of 2-Aryl-2<i>H</i>-indazoles Using Pinacol Mediated Deoxygenation of Nitroaromatics
作者:Dhananjaya Kaldhi、Raghuram Gujjarappa、Nagaraju Vodnala、Arup K. Kabi、Nayyef Aljaar、Chandi C. Malakar
DOI:10.1246/cl.190490
日期:2019.10.5
A molybdenum(VI)-catalyzed protocol for the synthesis of 2-aryl-2H-indazoles using pinacol as a reducing agent under neat reaction conditions has been demonstrated. The developed method gives an easy access to a wide range of 2-aryl-2H-indazoles in excellent yields. The present strategy excludes the use of P(III)-reagents as deoxygenating agents.
The reductive cyclization of o-nitrobenzylidene amines under microwave conditions employing MoO2Cl2(dmf)(2) as catalyst and Ph3P as reducing agent delivers 2-aryl-2H-indazoles with yields ranging from 61-92%.
An approach to fused pyrimidine derivativesvia Schiff bases of aromaticortho-nitrocarbaldehydes. An investigation of substituent effects on the reaction course