Novel Route to 2-Trifluoromethylated Benzofurans

Abstract

A novel route for the synthesis of a variety of 2-trifluoromethylbenzofurans is reported. By selection of solvents, the key intermediates, 2-chloro-3,3,3-trifluoropropenyl phenyl acetates, were cyclized either to give 2-trifluoromethyl-substituted benzofurans or to yield trifluoromethyl modified o-alkynylphenols. The latter intermediates could also be cyclized to give 3-iodo-2-trifluoromethyl-substituted benzofurans.

Keywords:

• o-Alkynylphenols
• iodocyclization
• phenyl acetates
• trifluoromethylbenzofurans

ACKNOWLEDGMENTS

We thank the National Analytical Research Center of Electrochemistry and Spectroscopy, Changchun Institute of Applied Chemistry, for support of this research.

Notes

^a Isolated yield.

^b The values in bracket are Z/E ratio of 2.

^a Reaction conditions: 2a (0.5 mmol) dissolved in 2 mL solvent, the base was added and the reaction was performed at room temperature.

^b GC yield.

^a Isolated yield.

^a Isolated yield.