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

Abstract

AbstractTreatment 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.magnified image