A facile construction of oxygen heterocycles by the reaction of benzoxepine-4-carboxylates with dihaloalkanes and activated alkynes.

This manuscript describes the preparation of heterocyclic compounds such as naphtho[1,3]-dioxoles (3a-h), [1,4]-dioxines (4a-h), [1,4]-dioxepines (5a-c), [1,4]-dioxocines (6a-c) and diethyl 2-(2-ethoxy-2-oxoethyl)naphtho[1,3]dioxoles (8a-f). These heterocyclic compounds have been achieved by the reaction of benzoxepine-4-carboxylates (1a-h) with dihaloalkanes (2a-e) and activated alkyne (7a) for the first time. This work represents the first example for the construction of utile oxygen heterocycles by the formation of C-C and C-O bonds in a one step process.