Synthesis of 4‐Chalcogenylated Isoxazoles Mediated by PhICl₂ and Diorganyl Disulfides/Diselenides

Abstract

This report described that a series of 4-chalcogenylated isoxazoles were readily synthesized from the one-pot reaction of alkynone Z-O-methyloximes with (dichloroiodo) benzene (PhICl 2 ) and diorganyl disulfides/diselenides under metal-free conditions. The reaction process was enabled by the electrophilic organosulfenyl chloride (RSCl) or selenenyl chloride (RSeCl) species, which were generated in situ from the reaction of PhICl 2 and diorganyl disulfides/diselenides. The striking feature of the approach is the in-situ formation of the electrophilic RSCl or RSeCl species, thus markedly decreasing the total usage of electrophiles when compared with the existing methods. This method exhibited a good functional groups tolerance for both alkynone Z-O-methyloximes and diorganyl disulfides/diselenides and the reaction could proceed at room temperature under ambient atmosphere within a short time to afford a series of functionalized isoxazoles in moderate to excellent yields.

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

“…Based on the experimental results described above as well as previous literature reports, 11,15 a plausible mechanism for this reaction is shown in Scheme 6 which involves R 3 XCl formation (step I) followed by a R 3 XCl-mediated electrophilic cyclization (step II). The intermediate A was formed through the attack of X (sulfur/selenium/tellurium) on the iodine center in PhICl 2 .…”

“…Because of the unstable properties of the sulfenyl chlorides or selenenyl chlorides, Du and co-works have developed a metal-free protocol about the in situ formation of PhXCl from PhXXPh and PhICl 2 to the synthesis of chalcogenides. 15 In recent years, one of the research focuses of our group is the construction of heterocyclic compounds based on the controllable functionalization of alkynes. 16 Inspired by the works above, herein, we report a simple metal-free method to afford the 3-selenyl/sulfenyl/telluriumindoles in the presence of the in situ generated ArSeCl, ArSCl, or ArTeCl from the reaction between the diselenides, disulfides, or ditellurides and PhICl 2 ( Scheme 2d ).…”

Recent Progress in Synthetic and Biological Application of Diorganyl Diselenides

“…[134] When alkynyl O-methyloximes were used as substrates in combination with diorganyl diselenides and iodobenzene dichloride, in dichloroethane, at room temperature, organoselenyl isoxazoles 92 were obtained (Scheme 87). [135] The improvements of this methodology include the in situ preparation of electrophilic organo-selenium species in transition-metal-free conditions, use of room temperature, ambient atmosphere, and short reaction time.…”