Synthesis of 2,3-Disubstituted 1,4-Naphthoquinones via Metal-Free C(sp2)-H Functionalization Followed by Suzuki Cross-Coupling Reactions

A synthetic strategy has been developed for the synthesis of 2,3-disubstituted-1,4-naphthoquinones. This synthetic protocol consists of metal-free tert-Butyl hydroperoxide (TBHP)-mediated oxidative benzoylation followed by Pd-catalyzed Suzukicross coupling reactions. Benzaldehyde, benzylalcohol and toluene were efficiently used as benzoyl radical source for the benzoylation of 1,4-naphthoquinones. By this protocol, a wide range of 1,4-naphthoquinones with different substitution patterns were efficiently prepared in a sequential way with good to excellent yields.