Selectfluor™-catalyzed oxidative cyclization of ynamides enables facile synthesis of oxazolidine-2,4-diones

Abstract

A Selectfluor™-catalyzed oxidative cyclization of ynamides employing DMSO as the solvent and oxidant was achieved, affording oxazolidine-2,4-diones in moderate to excellent yields with high chemo-selectivity. The method offers an attractive alternative to existing protocols.

Recent Advances in the Application of Selectfluor as a “Fluorine‐free” Functional Reagent in Organic Synthesis

“…Futhermore, a Selectfluor-catalyzed oxidative cyclization reaction of ynamide to oxazolidine-2,4-dione was studied by the Luo and He group (Scheme 20b). [39] The situ generated HBF4 from Selectfluor, DMSO, and water acted as a Lewis acid catalyst in this transformation.…”

PhB(OH)2-Promoted Electrochemical Sulfuration–Formyloxylation of Styrenes and Selectfluor-Mediated Oxidation–Olefination

“…Fortunately, when Selectfluor was added as an oxidant, sulfuration–formyloxylation products were smoothly converted to vinyl sulfones in nearly all quantitative yields without an additional base. Interestingly, this Selectfluor-mediated oxidation–olefination reaction of sulfides to synthesize vinyl sulfone has not been reported . As shown in Scheme , a wide range of thiophenols/thiols and olefins were applicable to generate vinyl sulfones in moderate to good yields ( 4a – 4k , 40–88%).…”

“…For the subsequent oxidation–olefination (Scheme ), the fluorinated reaction of 3a with Selectfluor furnishes the fluorosulfonium salt intermediate I-1 . Sulfoxide I-4 is generated through the nucleophilic addition of I-1 with H 2 O and HF elimination . Ammonium salt I-2 can be detected by ESI-MS analysis (Figures S5).…”

Highly Stereoselective Intramolecular Carbofluorination of Internal α,β-Ynones Promoted by Selectfluor

“…Traditional methods to construct monofluoroalkene compounds are based on olefination, elimination, or ring-opening reactions from fluorinated precursors. However, the regioselective synthesis of tetrasubstituted monofluoroalkene derivatives still represents a significant challenge . In the past few decades, carbofluorination of internal alkynes has provided a straightforward approach to obtain tetrasubstituted monofluoroalkenes via synchronous C–C and C–F bond formation (Scheme a).…”