A quick access to CF-containing functionalized benzofuranyl, benzothiophene and indolyl heterocycles under catalyst-free conditions.

A catalyst-free one-pot synthetic protocol is presented for the preparation of CF-containing benzofuran, indolin, and benzothiophene derivatives using readily available aromatic aldehydes and ketones. 2-Bromo-3,3,3-trifluoropropene was employed as a non-corrosive and environmentally benign trifluoromethylacetylene synthon for incorporation of the CF group. The reaction proceeds the formation of a suitably substituted 4,4,4-trifluoro-1-phenylbut-2-yn-1-ol intermediate, which undergoes 5- cyclization, resulting in an exocyclic double bond with -configuration.