Synthesis of Tri- and Tetrasubstituted Furans Catalyzed by Trifluoroacetic Acid

Substituted 2-hydroxy-3-acetylfurans are synthesized by alkylation of tert-butyl acetoacetate with an alpha-haloketone followed by treatment of the obtained intermediate with trifluoroacetic acid (TFA). A second alkylation of the intermediate followed by treatment with trifluoroacetic acid provides access to disubstituted 2-methylfurans.