Regioselective Decarboxylative Cycloaddition Route to Fully Substituted 3‐CF<sub>3</sub>‐Pyrazoles from Nitrilimines and Isoxazolidinediones
Yuchen Tian, Jun‐Kuan Li, Fa‐Guang Zhang, Jun‐An Ma
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
Topics & Concepts
ChemistryRegioselectivityCycloadditionAlkyl1,3-Dipolar cycloadditionArylMedicinal chemistryStereochemistryCombinatorial chemistryOrganic chemistryCatalysisFluorine in Organic ChemistryCyclopropane Reaction MechanismsCatalytic C–H Functionalization Methods