Regioselective Decarboxylative Cycloaddition Route to Fully Substituted 3-CF3-Pyrazoles from Nitrilimines and Isoxazolidinediones

Article abstract of DOI:10.1002/adsc.202100091

1,4-Diaryl-5-carboxamido substituted 3-trifluoromethylpyrazoles are obtained with exclusive regioselectivity under transition-metal-free conditions. This decarboxylative [3+2] cycloaddition protocol was enabled by employing trifluoromethyl nitrilimines as 1,3-dipoles, and isoxazolidinediones as CO₂-masked alkynyl dipolarophiles. The applicability of this method is further manifested by its compatibility with difluoromethyl, alkyl, aryl, and heteroaryl nitrilimines, as well as the preparation of 4-carboxylic amido analogue of drug Celebrex. (Figure presented.).