The Oxidation of (E)-α-Phenylcinnamic Acids with Manganese(III) Acetate

The oxidation of eight (E)-α-phenylcinnamic acids with manganese(III) acetate in boiling acetic acid containing acetic anhydride gave 3-phenylcoumarins, 3-phenyl-l-oxaspiro[4.5]deca-3,7,9-triene-2,6-diones, 2-phenylbenzofurans, 3-(acetoxymethyl)-2-phenylbenzofurans, 3-formyl-2-phenylbenzofuran, 2-acetoxy-2-phenyl-3 (2H)-benzofuranones, (Z)-α-acetoxystilbenes, 2-acetoxy-1,2-diphenylethanones, 5-acetoxy-4,5-diphenyl-2 (5H)-furanones, and diphenylacetylene. The reaction pathways are discussed.