Base-mediated [3+2]-cycloannulation strategy for the synthesis of pyrazolo[1,5-a]pyridine derivatives using (E)-β-iodovinyl sulfones

The pyrazolo[1,5-a]pyridines continuously occupy a special place in medicinal chemistry, but the direct construction of 3-sulfonyl analogues remains unexplored. Under basic conditions, the pyridinium-N-amine and corresponding dipolar aminide played a...