Iron(III) Chloride/Dialkyl Diselenides‐Promoted Cascade Cyclization of ortho ‐Diynyl Benzyl Chalcogenides

Treatment of ortho ‐diynyl benzyl chalcogenides with a mixture of iron(III) chloride and diorganyl diselenides led to functionalized chalcogen isochromene‐fused chalcogenophene derivatives. The reaction parameters were studied and the results indicated that the reaction of ortho ‐ diynyl benzyl chalcogenides (0.25 mmol) with iron(III) chloride hexahydrate (2.0 equiv.) and diorganyl diselenide (2 equiv.) at reflux of dichloroethane was the best condition to give the products in 40–83% yields. The results support the idea that a mixture of iron salts and diorganyl diselenides has a dual action, promoting the cyclization and introducing a new functionalization at the 3‐position of isochalcogenochromenes. The methodology was highly regioselective, giving the product via 6‐ endo ‐dig mode followed by a second cyclization via 5‐ endo ‐dig mode.