One-Pot Syntheses of Functionalized Dihydrobenzoselenophenes and Selenochromans from Acetyl Eugenol and Selenium Dibromide. Rearrangement of 2-(Bromomethyl)-2,3-dihydro-1-benzoselenophene to Selenochromans

Efficient methods for the synthesis of new fused heterocyclic compounds have been developed on the basis of annulation–functionalization of acetyl eugenol with selenium dibromide. The proposed procedures make it possible to obtain functional derivatives of dihydrobenzoselenophene and selenochroman containing bromo, methoxy, and acetoxy substituents with high yields in one preparative step. Nucleophilic substitution of bromine in 2-(bromomethyl)-5-methoxy-2,3-dihydro-1-benzoselenophen-6-ol has been found to involve ring expansion rearrangement with the formation of selenochroman derivatives.