Cu-Catalyzed Aerobic Oxidative C-H/C-O Cyclization of 2,2'-Binaphthols: Practical Synthesis of PXX Derivatives.

Cu-catalyzed C-H/C-O cyclization of 2,2'-binaphthol, using air as an oxidant, was developed. C-H functionalization of binaphthols occurred at the 8,8'-position to form peri-xanthenoxanthenes that exhibit high charge-carrier mobility. The reaction can tolerate a wide variety of functional groups and afforded the corresponding peri-xanthenoxanthene derivatives via an efficient procedure.