Metal‐Free, PhI(OAc)₂‐Promoted Oxidative C(sp²)−H Difunctionalization: Synthesis of Thioaminated Naphthoquinones

Abstract

A three-component thioamination reaction has been developed in the presence of phenyliodonium (III) diacetate (PIDA) leading to the formation of a thioaminated products. This catalytic approach represents a method for the metal-free thioamination of 1,4-naphthoquinone. It was observed that maleimides also work smoothly under this metal-free reaction condition. This present method implies the oxidative coupling reaction through a one-step process with the generation of CÀ N and CÀ S bonds. Various aromatic and aliphatic thiols and amines provided the corresponding thioaminated compounds in 62-88% yields. A plausible reaction pathway has been predicted according to few control experiments.

Updates on hypervalent-iodine reagents: metal-free functionalisation of alkenes, alkynes and heterocycles

“…Furthermore, various control experiments suggest the involvement of a non-radical reaction pathway (Scheme 6). 55…”

“…Furthermore, various control experiments suggest the involvement of a non-radical reaction pathway (Scheme 6). 55 In 2021, Zhang and co-workers reported HVI(III)-promoted difunctionalisation of alkenes leading to the synthesis of unsymmetric azo compounds (12) via a radical activation strategy. The methodology involves a rapid three-component cascade reaction of aryldiazonium salts (11) with unactivated alkenes and TMSN 3 .…”

Visible‐Light‐Mediated Self‐Sensitized Oxidative and Regioselective C(sp2)−H Selenylation and Sulfenylation of Substituted 2‐Amino‐1,4‐Naphthoquinones

“…2‐( p‐ Tolylamino)‐3‐( p ‐tolylthio)naphthalene‐1,4‐dione (3’ j) [16] . Brownish red color solid; yield 74 % (59 mg, 0.2 mmol scale, White LEDs ); 72 % (58 mg, 0.2 mmol scale, Sunlight ); mp : 47–49 °C.…”

Silver-Catalyzed, One-Pot, Three-Component Difunctionalization of Quinones: Synthesis of Indole-Functionalized p-Iminoquinone Derivatives

“…In 2002, Theodorakis and co-workers reported alkylation and thioetherification of quinones by photochemical decarboxylation of thiocarbonyl derivatives (Scheme 1a). 8 In 2019 9 and 2021, 10 the group of Chen developed a copper-catalyzed, one-pot, three-component thioamination of 1,4naphthoquinone with thiols and amines, and Majee reported a metal-free, one-step protocol for thioamination of 1,4naphthoquinone in the presence of PIDA (Scheme 1b and d).…”