Electrocatalytic Tandem Synthesis of 1,3-Disubstituted Imidazo[1,5-a]quinolines via Sequential Dual Oxidative C(sp3)–H Amination in Aqueous Medium

Abstract

An NH4I-mediated tandem electrosynthesis of 1,3-disubstituted imidazo­[1,5-a]­quinolines was developed from readily available starting materials in aqueous medium, affording a variety of 1,3-disubstituted imidazo­[1,5-a]­quinolines with good to excellent yields.

Diiodine-Mediated Oxidative Reaction for the Construction of Imidazo[1,5-a]pyridines under Metal-Free Conditions

“…Later, in 2019, Wang and co-workers continued exploring this topic and reported a tandem electrosynthesis of imidazo[1,5-a]quinolines mediated by NH 4 I in the absence of external chemical oxidants. 11 This method was metal-and hydroperoxide-free, and electricity was used to promote a strong redox reaction, maintaining excellent yields (Scheme 1d). However, the use of electricity also led to the need for complex reactors.…”

Recent Applications of Quinolinium Salts in the Synthesis of Annulated Heterocycles

“…A fascinating reaction of quinoline derivatives 62 with amines 63 under electrocatalytic condition was studied by Wang and co-workers. 53 In this transformation, a library of 1,3-…”

Organic Electrosynthesis Towards Sustainability: Fundamentals and Greener Methodologies

“…In the field of halogen catalysts, iodide ions were lately applied in the amination with dehydrogenation of Csp 3 −H bonds to form nitrogen heterocycles, such as pyrrolidines and oxazolines, through a dual photoelectrochemical process [121] . Likewise, Wang and coworkers described the electrocatalytic tandem synthesis of 1,3‐disubstituted imidazo[1,5‐ a ]quinolines via a sequential dual oxidative C(sp 3 )−H amination in aqueous medium under the same iodide mediation (Scheme 24a) [122] . Aryl iodides have behaved as suitable electrochemical mediators and sustainable oxidation catalysts that, via hypervalent iodine species, disclose trifluoroethoxy‐ and fluoro‐cyclizations, [123] enantioselective lactonizations and important procedures such as carbazole (Scheme 24b) [124] or benzoxazole syntheses [125]…”