Palladium-Catalyzed Equilibrium Addition of Acidic OH Groups across Dienes

Abstract

Mildly acidic O-H groups undergo transition-metal-catalyzed reversible addition across the C=C bonds of cyclic and acyclic dienes. For example, the simple complex [Pd(PPh3)4] (1 mol%) effectively catalyzes both the forward addition of phenol across dienes and the reverse elimination of phenol from allylic ethers (see scheme).