Expedient regioselective synthesis of all-different tetraaryl furans.

In addition to the all-different tetraaryl dihydrofuran esters prepared by our previously reported annulative Cloke-Wilson rearrangement, we developed a practical and efficient route to all-different tetraaryl furans. This strategy involves the removal of the ester on the quaternary β-carbon via either saponification or tBuOK-mediated decarbonylation of the derived aldehydes, followed by DDQ-mediated oxidative aromatization, or aerobic Ma oxidation of the derived alcohols. Notably, the method tolerates cross-coupling-reactive aryl halides, providing an efficient strategy for the synthesis of these all-different tetraaryl furans.