Merging Photochemistry with Electrochemistry: Functional‐Group Tolerant Electrochemical Amination of C(sp³)−H Bonds

Abstract

Scheme 2. Substrate scope of iodide-mediated dehydrogenative amination. The reactions were conducted on a0 .5 mmol scale. See the SupportingInformation for details. All yields are those of the isolated products. [a] 2a has also been produced under conditionswith stoichiometric chemical oxidants:PhI(OAc) 2 /cat. I 2 ,9 0%; [11a] PhI(OAc) 2 /I 3 À ,9 3%; [10g] mCPBA/cat. I 2 ,5 4%; [11c] [b] dr = 1:1. [c] dr = 1.8:1. [d] dr = 1.2:1. [e] With 2,6-lutidine instead of pyridine as additive. TsOH = p-toluenesulfonic acid.Scheme 3. Simplified mechanism for photo/electrochemical iodidemediated dehydrogenative CÀH/NÀHcoupling. Scheme 4. CVsofiodide and representative substrates.C onditions: 5mm substate in acetonitrile with KPF 6 (0.1 m)a ss upportingelectrolyte, glassy carbon as working electrode ( % 7.0 mm 2 ), and aplatinum wire counter electrode, scan rate = 100 mVs À1 .

Tandem photoelectrochemical and photoredox catalysis for efficient and selective aryl halides functionalization by solar energy

“…To exploit solar spectrum for sustainable organic transformation, we initiated a coupled photoelectrocatalytic/photocata-lytic strategy that complements the advantages of photoelectrocatalysis and photoredox catalysis. It is anticipated that (1) the tandem system constructed by a photocatalyst and a photoelectrode with wide-spectral response would enable the solar energy to be fully utilized, which is unavailable for photocatalysis or electrophotocatalysis; [34][35][36][37][38][39][40] (2) if the resulting photocatalyst intermediate would be able to response to light, the second photoexcitation of the intermediate can achieve higher reducing ability for more challengeable chemical reactions in an energy-efficient way; (3) sacrificial reagents-free conditions would avoid competitive side reactions caused by the oxidation/reduction products of sacrificial reagents, thus improving the chemoselectivity; and (4) the combination of inorganic materials and organic molecules would enrich the application of photoelectrochemical cells in organic synthesis. Specifically, taking reductive coupled photoelectrochemical/photoredox catalysis (c-PEC/PC) as an example (Figure 1B), the narrow bandgap photocathode can absorb wide spectrum of sunlight to excite electrons in the valence band (VB) to the conduction band (CB).…”

Organic Electrochemistry: Molecular Syntheses with Potential

“…The use of a dual electrocatalysis approach by electrophotochemistry 27 , 34 , 60 broadens the possibilities for elegant reaction design and expands the viable scope of photoredox catalysis. While important contributions for electrophotosynthesis have been made by inter alia Xu, 61 , 62 Lambert, 63 Lin, 64 , 67 Wickens, 65 and our group, 66 among others, 34c , 34d selected examples shall be discussed in the following section.…”

“… 33 Specifically, electrophotochemistry combined the electrochemical and photochemical steps in tandem pathways to generate a highly reactive intermediate, thus providing new avenues for contemporary reaction design and molecular transformations. 27 , 34 The merger of electrosynthesis with transition metal catalysis enabled novel resource-economic bond functionalizations, which unearthed a variety of new reaction mechanisms. 35 Electrochemical reduction shows largely untapped potential for reductive organic syntheses through cathodic reduction with the aid of a sacrificial anode material.…”

Electrochemical organic reactions: A tutorial review

“…Another work on oxidative C(sp 3 )-H/N-H cross-coupling of imidazopyridines with diarylamines was reported by the same group ( Liu et al, 2019 ). There have been numerous reports on dehydrogenative C(sp 3 )-H/N-H cross-coupling ( Wang and Stahl, 2019 ). The Lin group reported electrochemical diazidation of alkenes using an Mn-based catalyst ( Fu et al, 2017 ).…”