Solvent-dependent copper-catalyzed synthesis of pyrazoles under aerobic conditions. Issue 98 (2nd November 2016)

• Record Type: Journal Article
• Authors: Pünner, Florian; Sohtome, Yoshihiro; Sodeoka, Mikiko
• Is Part Of: Chemical communications. Volume 52:Issue 98(2016)
• Page Start: 14093
• Page End: 14096
• Publication Date: 2016-11-02
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/c6cc06935e
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : We have developed a copper-catalyzed oxidative cyclization of hydrazones under aerobic conditions, enabling solvent-dependent selective synthesis of different pyrazoles. Abstract : We present a copper-catalyzed oxidative cyclization of β, γ-unsaturated hydrazones, utilizing molecular oxygen as a stoichiometric oxidant. The methodology provides distinct classes of pyrazoles simply by changing the reaction solvent. Tris-substituted pyrazoles, having a ketone functionality at the C-5 position, were obtained as the major product in ethanol, while di-substituted pyrazoles were predominantly formed in 1, 1, 1, 3, 3, 3-hexafluoro-2-propanol.