Visible-light-induced self-catalyzed fluoroalkylation/cyclization of N-arylcinnamamides: synthesis of fluoroalkyl-containing 3,4-disubstituted dihydro-1,5-naphthyridin-2(1H)-ones and 7,8-disubstituted dihydropyrido[3,2-d]pyrimidin-6(5H)-ones

Abstract

A novel visible-light-mediated fluoroalkylation/cyclization tandem process for constructing fluoroalkyl-containing 3,4-disubstituted dihydro-1,5-naphthyridin-2(1H)-ones and 7,8-disubstituted dihydropyrido[3,2-d]pyrimidin-6(5H)-ones has been explored. This method is compatible with a wide range of N-arylcinnamamides as well as sodium fluoroalkylsulfonates (RfSO₂Na, Rf = CHF₂, CF₃, C₄F₉, C₆F₁₃) and avoids the need for any external oxidant or photocatalyst. Mechanism studies revealed that the singlet oxygen coexists with the superoxide radical anion through energy transfer and single electron transfer processes during the photoredox reaction.