Palladium‐Catalyzed Dehydrogenation of Benzyl Alcohols for Construction of 2‐Arylbenzimidazoles “On Water”

An “on water” synthetic strategy for the selective construction of 2‐arylbenzimidazoles involving the dehydrogenation of benzyl alcohols by a π‐benzylpalladium(II) system has been developed. This simple oxidant‐ and base‐free protocol can be achieved under mild conditions in an atom‐economic process from o‐phenylenediamines and benzyl alcohols, affording the desired products in moderate to excellent yields. Notably, the “on water” protocol is essential for achieving this new synthetic method in our catalytic system. An “on water” strategy for the selective synthesis of 2‐arylbenzimidazoles involving the dehydrogenation of benzyl alcohols by a π‐benzylpalladium(II) system has been developed.