Iron(III) Chloride Catalyzed Oxidative Coupling Reaction of 1,2-Diarylethylene Derivatives



A nontoxic FeCl3 catalyzed intramolecular oxidative coupling reaction was developed for mild synthesis of a series of phenanthrenes with different substituents. The method involves cross dehydrogenative coupling of a variety of 1,2-diarylethylene derivatives with di-tert-butylperoxide (DTBP) as a sole oxidant at room temperature in CH2Cl2/TFA (9:1 V/V) to yield phenanthrenes in good to excellent yields.