Thermal Ring Expansion of 2-Azidoselenochromenes: First Synthetic Examples of 1,3-Benzoselenazepines

Abstract

The thermolysis of 2-azido-2-tert-butyl-2H-selenochromenes (2a, b), which were easily obtained by the reaction of the corresponding 1-benzoselenopyrylium salts (1) with sodium azide, resulted in a ring expansion to give the novel stable 1,3-benzoselenazepines (5a, b) with denitrogenation in good yields.