Réactivité dipolaire-1,3 du 4,4,4-trichiloro-3-éthoxycarbonylamino-2-diazobutyrate d'éthyle issu de l'action du diazoacétate d'éthyle sur la N-éthoxycarbonyl-N-(2,2,2-trichloroéthylidène)amine

Abstract

The reaction of ethyl diazoacetate with the N-ethoxycarbonyl-N-(2,2,2-trichloroethylidene)amine yields, by a nucleophilic addition, a new diazo compound that gives 1,3-dipolar cycloaddition reactions with acetylenic esters and maleimides. With acetylenic esters, the cycloadduct leads to substituted pyrazoles by [1,5] sigmatropic rearrangements. With maleimides, we observe a diastereospecific cycloaddition reaction. The intermediary cycloadduct evolves by nitrogen elimination to give a maleimidocyclopropane. The diastereospecificity was explained by an endo-anti approach of the reactants. Keywords: N-ethoxycarbonyl-N-(2,2,2-trichloroethylidene)amine, ethyl diazoacetate, nucleophilic addition, 1,3-dipolar cycloaddition, sigmatropic rearrangement, diastereoselectivity.

[2 + 3]‐Cycloadditions of Diazoalkanes with Imines of Hexafluoroacetone and Chloral.

“…Similarly, reactions of chloral imines (2,2,2-trichloroethylidene amines) with diazo compounds are rarely described and, to the best of our knowledge, are limited to N-methoxycarbonyl chloral imine [6,19]. In one case, the reaction with diphenyldiazomethane yielded a 1,2,4-triazole derivative, which easily eliminated nitrogen.…”