Synthesis of 3-selanyl-isoflavones from 2-hydroxyphenyl enaminones using trichloroisocyanuric acid (TCCA): a sustainable approach

Abstract

We hereby present an original and sustainable synthetic methodology for the synthesis of 3-selanyl-isoflavones from 2-hydroxyphenyl enaminones and diorganoyl diselenides. The reaction is promoted in a one-pot manner by the...

Selectfluor-mediated tandem cyclization of enaminones with diselenides toward the synthesis of 3-selenylated chromones

“…On the basis of these results and previous reports, 19–23 a plausible mechanism for this transformation was proposed (Scheme 4). Initially, the reaction involves the oxidation of diphenyl diselenide by Selectfluor reagent to form the electrophilic species I and II .…”

“…22 Very recently, Braga's group developed trichloroisocyanuric acid (TCCA)-mediated synthesis of 3-selenochromones from 2-hydroxyphenyl enaminones with diaryl diselenides (Scheme 1d). 23 Regardless of their merits, the current strategies suffer from some disadvantages such as transition-metal as a catalyst, limited substrate scope, the inevitability of a strong oxidant, high reaction temperature, or complex reaction conditions. Therefore, more general and mild approaches for the construction of diversely 3-selenochromones are yet highly desirable to satisfy the requirement of discovering more chromone-based functional molecules or lead compounds.…”

3‐Halochromones Through Oxidative α‐Halogenation of Enaminones and its Photophysical Investigation: Another Case of Photo‐induced Partially Aromatised Intramolecular Charge Transfer?

“…Recently, we reported the synthesis of 3-selanyl-chromones through intramolecular cyclisation of 2-hydroxyphenyl enaminones promoted by an electrophilic selenium species. [19] Therefore, we decided to evaluate the same approach searching for eco-friendly processes to generate electrophilic halogen species. In the present paper, we report a new method for the synthesis of various 3-chloro-, 3-bromo-, and 3-iodochromones using Oxone® as a green oxidant with halide salts.…”

“…Recently, we reported the synthesis of 3‐selanyl‐chromones through intramolecular cyclisation of 2‐hydroxyphenyl enaminones promoted by an electrophilic selenium species [19] . Therefore, we decided to evaluate the same approach searching for eco‐friendly processes to generate electrophilic halogen species.…”

Ag(i)-catalyzed three-component radical cascade synthesis of 3-organoselenyl chromones from 2-methoxyaryl alkynones, Se powder and organic boronic acids

“…Considering that RSeSeR was not commercially available, Zhang and co-workers 9 also recently improved this approach by their pre-preparation from excessive organic boronic acids and Se powder, followed by oxidation with PIFA and cyclization in one pot. The second one was the electrophilic cascade cyclization of 2-hydroxyaryl enaminones with organoselenium cations, which were in situ generated either from RSeCl and AgOTf, 10 or from RSeSeR by oxidation with TCCA, 11 or by air under the catalysis of KNO 3 12 or light irradiation 13 (Scheme 1b). The last one was the direct selenylation of preformed chromone rings with organoselenium radicals or anions, derived from RSeSeR, 14 sodium seleninate, 15 KSeCN/ArI, 16 or Se powder/ArI, 17 via various oxidative or Cu-catalyzed C–H bond active strategies (Scheme 1c).…”