Treatment of the azido (2-heteroaryl) methanones 1–5 with methyl (E)-3-pyrrolidinoprop-2- enoate at room temperature yielded the methyl 1, 2, 3-triazolecarboxylate 6 and (2- heteroaryl)(pyrrolidino) methanones 1a–5a via an unusual 1, 3-cycloaddition reaction. Analogous reactions of the azidomethanones 1 and 2 with the dipolarophiles methyl crotonate, methyl propiolate or methyl but-2-ynoate failed. In contrast, the strained 5- ...
