Catalyst-Free Formation of Nitrile Oxides and Their Further Transformations to Diverse Heterocycles
作者:Luca De Angelis、Alexandra M. Crawford、Yong-Liang Su、Daniel Wherritt、Hadi Arman、Michael P. Doyle
DOI:10.1021/acs.orglett.0c04130
日期:2021.2.5
transfer from tert-butyl nitriteundermildconditions and without the use of a catalyst or an additive is reported. This transformation is broadly applicable to the synthesis of furoxans by dimerization and isoxazoles and isoxazolines by cycloaddition. This methodology is also applied for the millimole-scale synthesis of two biologically active compounds. The formation of the nitrile oxide from a diazoacetamide
gel-supported sodium hydrogen sulfate (NaHSO4/SiO2) or Amberlyst 15 as solid acid catalyst, and then the corresponding 3-acylisoxaszoles were obtained by reacting with alkynes via the 1,3-dipolar [3+2] cycloaddition. These heterogeneous catalysts are easily separable from the reaction mixture and reused. This synthetic method provides a facile, efficient, and reusable production of 3-acylisoxazoles.
accomplished. This chemistry is operative under the cooperative catalysis of cupric oxide nanoparticles (<50 nm) and DABCO. The key beneficial aspects of this protocol include: (i) broad substrate scope, (ii) no vigorous work-up, (iii) short reaction time, (iv) solvent-free condition, (v) commercial viability of substrates/reagents (vi) good chemical yields and selectivity. The other merit of this chemistry
Application of silica gel-supported polyphosphoric acid (PPA/SiO2) as a reusable solid acid catalyst to the synthesis of 3-benzoylisoxazoles and isoxazolines
3-Benzoylisoxazoles were synthesized by the reaction of alkynes and benzoylnitromethane using silica gel-supported polyphosphoric acid (PPA/SiO2). This reaction provides a convenient, efficient, and reusable synthetic method of isoxazole derivatives. (C) 2011 Elsevier Ltd. All rights reserved.
Dybova; Yurchenko; Gritsai, Russian Journal of Organic Chemistry, 1998, vol. 34, # 5, p. 642 - 646