Concise total synthesis of honokiol via Kumada cross coupling

A concise four-step efficient synthesis of honokiol 1 in 68% overall yield is described here. The present method involves tetrakis(triphenylphosphine)palladium [Pd(Ph-3)(4)] catalyzed Kumada coupling in two key steps. First coupling generates biaryl backbone intermediate 5 and second generates 2,4'-O-dimethylhonokiol 3. Final demethylation under AlCl3/DMS condition affords honokiol in quantitative yield. (C) 2014 Elsevier Ltd. All rights reserved.