Synthesis of 6H-Benzo[c]chromenes via Palladium-Catalyzed Intramolecular Dehydrogenative Coupling of Two Aryl C-H Bonds

The palladium-catalyzed intramolecular C-H/C-H coupling reaction of two simple arenes to generate 6H-benzo[c]chromenes has been reported for the first time. The approach features broad substrate scope and good tolerance of functional groups and uses molecular oxygen as the terminal oxidant. The high efficiency of the approach is verified by concise total synthesis of natural product cannabinol.