Simple and highly efficient synthesis of oxaziridines by tetrabutylammonium Oxone®
摘要:
Oxygenation of various aldimines with tetrabutylammonium monoperoxysulfate produced the corresponding E- or a Mixture of E- and Z-oxaziridines with very high yields (greater than or equal to90%) and good to excellent selectivities (75-100%) within 20 min to 10 h in CH3CN at room temperature (similar to25 degreesC). The E/Z isomer ratio critically depends on the stereo-electronic nature of the substituents in the oxaziridines, solvent, and the presence of Lewis acids and bases. (C) 2003 Elsevier Ltd. All rights reserved.
A convenient method for the synthesis of 2-alkyl-3-aryloxaziridines 1 based on the formation of stable azomethines and their oxidation with m-chloroperoxybenzoic acid is reported. The scope and limitation of the method proposed is illustrated with numerous examples.
Synthesis of stable isoxazolines by [3+2] cycloaddition of oxaziridines with alkynes
作者:Marilena Fabio、Ludovico Ronzini、Luigino Troisi
DOI:10.1016/j.tet.2008.03.092
日期:2008.5
N-Alkyl substituted oxaziridines undergo a [3+2] cycloaddition reaction with a variety of terminal alkynes to give the product isoxazolines, whose stability appears to depend on the electronic properties of the groups on the C-3 and C-5 positions. The presence of an electron withdrawing group on C-5 and/or an electron donating group on C-3 causes isomerization of the isoxazolines to β-amino enones