Visible Light/Tertiary Amine Promoted Synergistic Hydroxydifluoroacetamidation of Unactivated Alkenes under Air

Abstract

An efficient and novel method for regioselective hydroxydifluoroacetamidation of alkenes with bromodifluoroacetamides has been achieved via a tandem radical pathway mediated by photoredox catalysis under metal-free conditions. This transformation proceeded smoothly in the presence of Rhodamine 6G, affording a series of α,α-difluoro-γ-hydroxyacetamides in moderate to excellent yields. The significant advantages of this protocol are the low-cost photocatalyst, readily available starting materials, synthetic convenience, and wide functional group compatibility.

Copper and Photocatalytic Radical Relay Enabling Fluoroalkylphosphorothiolation of Alkenes: Modular Synthesis of Fluorine-Containing S-Alkyl Phosphorothioates and Phosphorodithioates

“…In light of these preliminary findings and previous work, , a mechanistic scenario is outlined in Scheme c. First, with blue light irradiation, Ir III is excited to Ir III * ( E 1/2 = −0.96 V vs SCE), which then reduces BrCF 2 COOEt ( E 1/2 = −0.57 V vs SCE) to generate an ethyl difluoroacetate radical and the oxidized photocatalyst Ir­(IV) via a single-electron transfer pathway.…”

“…The direct transformation of activated and unactivated alkenes into diverse phosphorothioates would undoubtedly be highly attractive yet challenging . In the past few years, alkene difunctionalizations have emerged as a powerful tool for rapid assembly of molecular complexity, and various valuable fluorinated molecules have been obtained efficiently through difunctionalization-type fluoroalkylation of alkenes. − Recently, we reported a copper-catalyzed radical relay trifluoromethylphosphorothiolation of alkenes with Togni reagent II and P­(O)­SH generated in situ from reaction of P­(O)H with S 8 , providing a facile access to diversified β-CF 3 -substituted S -alkylphosphorothioates (Scheme c) . Compared with Togni reagents, fluoroalkyl halides such as monofluoroalkyl bromides, difluoroalkyl bromides, trifluoromethyl iodide, or perfluoroalkyl iodides are inexpensive and readily available starting materials, thus expanding the scope of F-containing groups.…”

Radical Perfluoroalkylation of Aliphatic Substrates

“…III traps oxygen to render peroxyl radical intermediate IV, which ultimately gives intermediate V (after homolytic cleavage of the tetraoxo dimer produced from intermediate IV). 124 V is reduced by the radical cation of DIPEA to the final product. The DIPEA radical cation originates as a byproduct from the visible light irradiation of the EDA complex between DIPEA and R F −I, which in turn affords a second R F radical.…”

Directed Nickel-Catalyzed Selective Arylhydroxylation of Unactivated Alkenes under Air

“…As two of the most basic and abundant chemical bonds, carbon–carbon and carbon–oxygen bonds exist widely in nature. The carbooxygenation of alkenes represents a powerful and attractive synthetic tool for simultaneous formation of C­(sp 3 )–C­(sp/sp 2 /sp 3 ) and C­(sp 3 )–O bonds in one sequence . Among these reactions, the arylhydroxylation of alkenes that introduce vital aryl and hydroxyl groups across the double bonds has attracted considerable interest.…”