A Novel and Efficient Route for the Synthesis of Hydroxylated 2,3-Diarylxanthones

A novel, efficient and general route for the synthesis of hydroxylated 2,3-diarylxanthones is described. 3-Bromo-2-styrylchromone, the key intermediate of this synthesis, is obtained by a Baker-Venkataraman rearrangement of the appropriate 2′-cinnamoyloxyacetophenone, followed by a one-pot reaction with phen-yltrimethylammonium tribromide. The Heck reaction of these bromochromones with substituted styrenes gives methoxylated 2,3-diarylxanthones. The cleavage of the methyl groups with BBr 3 gives the desired hydroxylated 2,3-diarylxanthones.