One‐Pot Two‐Step Synthesis of Isochromene‐Fused CF3‐Substituted Pyrazoles

An efficient one-pot, two step method for fusing two biologically active motifs, CF3-substituted pyrazoles and isochromenes, was developed. SelectiveO-benzylation of CF3-substituted pyrazolones and subsequent Pd-catalyzed direct C-H arylation generate a fused tricycle. For the synthesized compounds through-space(13)C-F-19 spin-spin coupling was revealed. In addition, the synthesis of three thioisochromene analogues, and one isocoumarin derivative, was accomplished.