Radical-mediated [3 + 2 + 1] annulation of α-polyfluoromethyl alkenes with arylisocyanates enabled by C(sp3)–F activation

Abstract

Direct C(sp³)–F functionalization represents an attractively powerful technology for further modification to construct diverse value-added fluorinated structures and enable environmentally persistent fluorinated molecule degradation. However, direct C(sp³)–F activation of alkenyl-CF₃via single electron transfer (SET), which would serve as a straightforward tool for cleavage of the C–F bond to form a carbon-centered radical, remains elusive. Herein we disclose a SET by DMF and Na₂CO₃ for selective C(sp³)–F activation, enabling [3 + 2 + 1] annulation of α-polyfluoromethyl alkenes with arylisocyanates for producing monofluorinated 3,4-dihydropyrimidin-2(1H)-ones. Mechanistic studies by the EPR analysis and DFT calculations show that this method uncovers a SET strategy that is capable of activating C(sp³)–F bonds to enable the formation of polyfluoromethyl radicals.