Kumar G.Ray S.Saha S.Shankar Singh M.2025-01-132025-01-13202421935815https://dl.bhu.ac.in/ir/handle/123456789/1853An efficient one-pot synthesis of 1H-pyrazoles has been realized via cascade cyclocondensation of ?-nitroalkenes as C2 synthon with ?-diazoesters as C1N2 unit. The reaction proceeds via concomitant formation of two new (C?N & C?C) bonds in one stretch leading to ethyl-5-nitro-4-phenyl-4,5-dihydro-3H-pyrazole-3-carboxylate intermediate, which undergoes base mediated denitration enabling the formation of NH?pyrazoles. This protocol not only features easy operation, catalyst?free conditions, good to high yields, wide scope and late-stage functionalization, but also opens up a new avenue for synthetically demanding and structurally non-traditional pyrazoles. A combination of experimental and DFT studies provide evidence for the proposed mechanism. � 2024 Wiley-VCH GmbH.en1,3-Dipolar cycloadditionDFT StudiesNitroalkenesPyrazolesRegioselective?-DiazoestersArticle10.1002/ajoc.202400077