Metal-free synthesis of sulfonylated indolo[2,1-a]isoquinolines from sulfur dioxide

Abstract

Access to sulfonylated indolo[2,1-a]isoquinolines through an efficient three-component reaction of 2-aryl-N-acryloyl indoles, sulfur dioxide and aryldiazonium tetrafluoroborates is developed. This transformation is performed under metal-free and mild conditions by using...

The Application of Sulfonyl Hydrazides in Electrosynthesis: A Review of Recent Studies

“…In 2019, Lee reported an electrochemical synthetic protocol for the sulfonylation of tertiary amines toward β-amido-vinyl sulfones, using sulfonyl hydrazides (81) and tertiary amines (82) as substrates (Scheme 11). 67 To realize the protocol, the substrates were treated in an undivided cell equipped with a graphite anode and a Pt cathode with a constant current of 5 mA (6.2 F mol −1 ) in DMSO under an acidic condition (acetic acid).…”

“…It was indicated that the key steps in this reaction involved sulfonyl radical's addition to alkene, which was generated by the electro-oxidation of tertiary amines in situ. At the early stage, sulfonyl hydrazides (81) and tertiary amines (82) were oxidized at the anode and gave sulfonyl radicals (84) and alkenes (87) respectively, and then the addition took place and yielded carbon radical intermediates (88). Then the intermediates (88) underwent with an oxidation and elimination sequence and afforded the target compounds.…”

“…Compounds with indolo-[2,1- a ]-isoquinolines structures showed excellent bioactivity and attracted much attention from synthetic chemists. − In 2020, Xia and co-workers developed an electrosynthesis route of indole derivatives choosing sulfonyl hydrazides ( 160 ) and 2-aryl- N -acryloyl indole derivatives ( 161 ) as substrates (Scheme ). To achieve the goal, the reactions were carried out in an undivided cell charged with a Pt anode and a Pt cathode under a constant current of 10 mA in a mixed solvent of THF/H 2 O (3:1, v/v), and KI was used as an electrolyte.…”

Regioselective intramolecular cyclization of o-alkynyl arylamines with the in situ formation of ArXCl to construct poly-functionalized 3-selenylindoles

“…As an active nitrogen-containing heterocyclic skeleton, indole exists widely in biologically active natural products and synthetic bioactive products, and represents an important “privileged scaffold”. 1 Among the numerous indoles, 3-arylselenoindoles are particularly attractive due to their potential use in therapeutics such as anti-oxidant, anti-tumor, and anti-cancer agents. 2 For example, as a novel combretastatin-like drug, 3-selenylindole compound (I) exhibits highly potent inhibitory activity against cancer cells 3 ( Scheme 1 ).…”

Metal-free hydrosulfonylation of α,β-unsaturated ketones: synthesis and application of γ-keto sulfones

“…In the past decades, a variety of protocols have been developed to construct β-keto sulfones. 8 Whereas succinct synthetic routes toward structurally related γ-keto sulfones are scarce, 9 traditionally, γ-keto sulfones were synthesized via the nucleophilic substitution of sodium sulfinates by 2-chlorovinyl ketones, 10 the elimination of the bromo derivatives of saturated keto sulfones 11 and the oxidation of the corresponding sulfides or sulfoxides. 12 However, the principal drawback is that these procedures were strongly limited by multiple steps, narrow substrate scope, or poor stereoselectivity.…”