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

Abstract

Abstract 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 CO 2 ‐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. magnified image