Synthesis of fluorenones by using Pd(II)/Mg–La mixed oxide catalyst

Palladium(II)/magnesium–lanthanum mixed oxide (Pd(II)/Mg–La mixed oxide) catalyst was used in the dehydrogenative cyclization of benzophenones to afford fluorenones. This protocol represents a direct and facile approach to accessing a variety of fluorenone derivatives by means of C–H activation under heterogeneous conditions. The catalyst was recovered by centrifugation and used for three consecutive cycles with nearly consistent activity and selectivity.