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We describe here for the first time the synthesis of isochromenones fused to selenophenes. 5H‐Selenopheno[3,2‐c]isochromen‐5‐ones were obtained through a double intramolecular cyclization of methyl 2‐(organyl‐1,3‐diynyl)benzoate promoted by electrophilic species of selenium generated in situ by the reaction of dialkyl diselenides with Oxone®, using ethanol as solvent. The reactions were conducted satisfactorily under mild conditions, using a range of 1,3‐diynes and dialkyl diselenides as substrates. A total of sixteen unprecedent 5H‐selenopheno[3,2‐c]isochromen‐5‐ones were selectively obtained in moderate to good yields (40–86%) under reflux in an open flask and in short reaction times (1.0–2.5 h). [ABSTRACT FROM AUTHOR]

A simple and efficient method for the synthesis of 4‑organoselanyl-1 H -pyrazoles has been developed, taking place under metal- and halogen-free conditions. Electrophilic species of selenium were easily generated in situ by the reaction of diorganyl diselenides with Oxone® in ethanol as solvent in an open-flask at 70 °C. These electrophilic selenium species were employed in the selenylation/cyclization of α,β-alkynyl hydrazones, giving the title compounds in moderate to excellent yields. The final species of selenium obtained from the reaction of diphenyl diselenide with Oxone® were characterized by77 Se NMR spectroscopy and high-resolution mass spectrometry (HRMS). [ABSTRACT FROM AUTHOR]

This paper describes an alternative method for the synthesis of 3-organoselanylbenzo[b]furans through the intra-molecular cyclization of 2-alkynylphenols promoted by copper iodide and diorganyl diselenides. The cyclization reactions were carried out at room temperature in the absence of base and under air (open flask). This synthetic approach proved to be efficient with both diorganyl diselenides and 2-alkynylphenols bearing electron-neutral, electron-donating, and electron-withdrawing substituents. 2-Phenyl-3-phenylselanylbenzo[b]furan was used as a synthetic precursor in organochalcogen--lithium exchange and bromination reactions, allowing the synthesis of functionalized benzo[b]furans in good yields. [ABSTRACT FROM AUTHOR]

The retro-Favorskii reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp−S or Csp−Se bonds were selectively prepared through the retro-Favorskii reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes were stable for weeks if stored as a solution in hexanes. [ABSTRACT FROM AUTHOR]