Electrochemical Minisci reactionviaHAT-driven α-C(sp³)–H functionalization of alcohols

Abstract

An efficient electrochemical Minisci reaction to access 3-hydroxyalkylquinoxalin-2(1H)-ones involved hydrogen atom transfer (HAT) driven α-C(sp3)−H functionalization of alcohols was achieved. Transition metal- and chemical oxidant-free conditions were the attractive synthetic...

HAT‐Promoted Electrochemical Amination: C(sp2)−H/N−H Cross Dehydrogenative Coupling

“…Based on these control experiments and related reports, [16] a possible mechanism for the electrochemical amination reaction is suggested as shown in Scheme 6. The TMSN 3 was reduced at the cathode to generate an azide anion intermediate I , which was oxidized at the anode to produce the azido radical intermediate II .…”

“…Some HAT reagents such as halogenide salts, [13] NHPI [14] and DABCO [15] were successfully used in the electrochemical C−H bond functionalization. In our recent works, a low toxicity, safe HAT reagent TMSN 3 was found and used to activate α‐C( sp 3 )−H of alcohols generating hydroxyalkyl radicals under the electrochemical conditions [16] . Herein, we report an electrochemical C−H/N−H CDC reaction via the TMSN 3 ‐driven N−H activation of amines to synthesize amino‐functionalized quinoxalin‐2(1 H )‐ones (Scheme 1d).…”

“…In our recent works, a low toxicity, safe HAT reagent TMSN 3 was found and used to activate α-C(sp 3 )À H of alcohols generating hydroxyalkyl radicals under the electrochemical conditions. [16] Herein, we report an electrochemical CÀ H/NÀ H CDC reaction via the TMSN 3 -driven NÀ H activation of amines to synthesize amino-functionalized quinoxalin-2(1H)ones (Scheme 1d).…”

Electrochemical Benzylic C(sp3)–H Amidation via Ritter-Type Reaction in the Absence of External Mediator and Oxidant

“…In 2020, we reported an electrochemical difunctionalization of alkenes via a four-component reaction to access functionalized imides, and one of the crucial steps in the proposed mechanism was the trapping of benzylic carbocation with CH 3 CN. 21a Based on this finding and our research on the electrochemical oxidative C–H functionalization of organic compounds, 21` c d e herein, we report an electrochemical Ritter-type benzylic C(sp 3 )−H amidation without external mediator and oxidant (Scheme 1h ).…”

Electrocatalytic synthesis: an environmentally benign alternative for radical-mediated aryl/alkenyl C(sp2)–C(sp3) cross-coupling reactions

“…Very recently, Sun et al exhibited an efficient and practical electrochemical C(sp 2 )–H/C(sp 3 )–H cross-coupling of quinoxalin-2(1 H )-ones with alcohols (possessing a α-C(sp 3 )–H bond) for the synthesis of 3-hydroxyalkylquinoxalin-2(1 H )-ones in the presence of 1,5 equivalent TMSN 3 (Scheme 19). 38 Gratifyingly, the reaction with methanol was also successful by fine tuning the electrochemical conditions, giving the structural diversity hydroxymethylated products in good to excellent yields. In this transformation, the additive TMSN 3 served as hydrogen atom transfer reagent to induce the generation of alkyl radical.…”