Synthesis of tetra-substituted 5-trifluoromethylpyrazoles via sequential halogenation/palladium-catalyzed C–C and C–N cross-coupling. Issue 7 (26th January 2016)

• Record Type: Journal Article
• Authors: Wiethan, Carson; Rosa, Wilian C.; Bonacorso, Helio G.; Stradiotto, Mark
• Is Part Of: Organic & biomolecular chemistry. Volume 14:Issue 7(2016)
• Page Start: 2352
• Page End: 2359
• Publication Date: 2016-01-26
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c5ob02390d
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : The assembly of tetra-substituted 5-trifluoromethylpyrazoles is presented, involving palladium-catalyzed Negishi or Buchwald–Hartwig cross-couplings to install carbon or nitrogen-based 4-substituents. Abstract : A mild and efficient protocol for the assembly of tetra-substituted 5-trifluoromethylpyrazoles is presented, involving halogenation at the 4-position of readily prepared tri-substituted 5-trifluoromethylpyrazoles to give 4-halo-1-phenyl-5-trifluoromethyl pyrazoles, and subsequent palladium-catalyzed Negishi or Buchwald–Hartwig cross-couplings to install carbon or nitrogen-based 4-substituents. Key to the success of these challenging cross-couplings is the use of XPhos and JosiPhos CyPF- t Bu ligands, respectively.