Base-Promoted Ecofriendly Synthesis of Trisubstituted Pyrazoles from α,β-Alkynyl N-Tosylhydrazones under Metal- and Solvent-Free Conditions
摘要:
A simple and green method is described for the synthesis of trisubstituted pyrazoles from ,-alkynyl N-tosylhydrazones under metal- and solvent-free conditions. Notably, only diisopropylamine is required as a promoter, and the reaction can be easily performed at room temperature and on a gram scale.
A facile and metal‐free access to pyrazoles from 1,3‐diarylpropenes and hydrazines via multiple inter‐/intramolecular C‐H aminations was described. Under the neutral and mild 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) oxidative conditions, various disubstituted pyrazoles were synthesized in moderate to excellent yields. This method provides a pot‐ and step‐economic strategy for the construction of
作者:Stanislav A. Paveliev、Oleg O. Segida、Oleg V. Bityukov、Hai‐Tao Tang、Ying‐Ming Pan、Gennady I. Nikishin、Alexander O. Terent'ev
DOI:10.1002/adsc.202200696
日期:2022.11.22
C(sp2)−H/N−H coupling of α,β-unsaturated hydrazones resulting in substituted pyrazoles has been discovered. The process is catalyzed by hypervalentiodinespeciesgenerated in situ through anodic oxidation of aryl iodide in fluorinated alcohol media. The formation of hypervalentiodine compound and its key role in the construction of a new C−N bond was confirmed with CV and NMR experiments. A wide range