Synthesis of Trifluoromethylated Dibenzoxepines via Palladium-Catalyzed Tandem C-O Bond Formation/C-H Arylation.

A palladium-catalyzed cyclization reaction of phenols with trifluoromethyl-containing ortho -bromo-β-chlorostyrenes has been developed. In the presence of palladium(II) acetate, tricyclohexylphosphine, and cesium carbonate, a variety of 6-trifluoromethyldibenzo[ b , d ]oxepines were prepared in moderate to good yields through the tandem O-alkenylation of general phenols and subsequent C-H arylation.