Synthesis of 3-Arylcoumarins by FeCl3-Promoted Cyclization of orto-Methoxy-Substituted (E)-2,3-Diphenylpropenoic Acids or Their Methyl Esters.

3-Arylcoumarins were conveniently synthesized in excellent yields by an iron(III) chloride-promoted tandem reaction using methoxy-substituted (E)-2,3-diphenylpropenoic acids or their methyl esters. The structure of 3-(4-methoxyphenyl)coumarin was established from X-ray crystallographic data.