Alkyl Propiolates Participated [3+2] Annulation for the Switchable Synthesis of 1,5-and 1,4-Disubstituted 1,2,3-Triazoles Containing Ester Side Chain

摘要

By means of a featured enamine activation, the alkyl propiolates have been successfully employed in the [3+2] annulation for the synthesis of 1,2,3-triazoles. The synthesis of both 1,4- as well as the hardly available 1,5-disubstituted 1,2,3-triazoles can be selectively accessed by using tosyl azide and tosyl hydrazine as nitrogen source, respectively.