1,3-DIPOLAR REACTIVITY OF ETHYL 4,4,4-TRI CHLORO-3-ETHOXYCARBONYLAMINO-2-DIAZOBUTYRATE FROM THE REACTION OF ETHYL DIAZOACETATE WITH -ETHOXYCARBONYL-N-(2,2,2-TRICHLOROETHYLIDENE)AMINE

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