Radical Addition/Cyclization Reaction of 2‐Vinylanilines with Alkynes: Synthesis of Naphthalenes via Electron Catalysis

Abstract

Ac ascade radicala ddition/cyclization reaction of 2-vinylanilines with alkynes for the synthesis of biologically important naphthalene derivatives is reported. In this transformation,t he in-situ-formed diazonium salts from 2vinylanilines served as efficient aryl radical precursors and the reactionwas rununder metal-free conditions. (0.4 mmol) in BTF (2.0 mL) were stirred at 70 8Cfor 24 hu nder argon atmosphere.[b] Isolated yield.[a] X.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Electron Donor–Acceptor Complex Enabled Decarboxylative Sulfonylation of Cinnamic Acids under Visible-Light Irradiation

“…Within the framework of our ongoing research interests devoted to the development of valuable and efficient radical reactions, we describe herein a visible-light-induced radical decarboxylative sulfonylation of cinnamic acids with aryl sulfonate phenol esters (Scheme c). It is worth noting that photoredox catalyst and oxidant were not required to run the reaction, and this transformation proceeded at room temperature under blue LED irradiation by the formation of an electron donor–acceptor (EDA) complex …”

Recent Development of Aryl Diazonium Chemistry for the Derivatization of Aromatic Compounds

“…Additionally, this radical [4 + 2] benzannulation procedure from ortho -amino-biphenyls and alkynes enables the expeditious synthesis of various benzo-fused ring scaffolds, affording phenanthrenes 97 , naphthalenes 98 , and tetrazolo­[1,5- a ]­quinoline 99 under light-free thermal conditions or at room temperature (Scheme ).…”

Recent advances in radical-mediated intermolecular (4 + 2) cycloaddition

“…In 2018, Xuan and co-workers reported an electron-catalyzed (4 + 2) cycloaddition reaction using non-metallic tetrabutylammonium iodide (TBAI) as an electron catalyst (Scheme 9). 18 In this reaction, 2-vinylaniline is generated as a diazonium salt in the presence of isoamyl nitrite, which produces an in situ aryl radical after single electron transfer from TBAI, and then immediately undergoes a radical addition reaction with an alkyne to produce alkenyl radical intermediate K . Next, the intermediate K is subjected to (4 + 2) cycloaddition to give the intermediate L .…”