Search

Terminal acetals were synthesized from various vinylarenes and 1,2- or 1,3-diols using a simple PdCl2(MeCN)2/methoxy- p-benzoquinone (MeOBQ)/CuCl catalyst system and 1 atm of O2 under mild reaction conditions by the anti-Markovnikov nucleophilic attack of an oxygen nucleophile on the coordinated vinylarenes. Cyclic α,β-unsaturated carbonyl compounds such as MeOBQ and N-phenylmaleimide were especially effective as additives to afford higher yields of the desired terminal acetals. Kinetic experiments indicated that MeOBQ operates as a π-acceptor ligand for Pd to accelerate the reaction and that the dissociation of a chloride ion from Pd precedes the rate-determining step. [ABSTRACT FROM AUTHOR]

The Front Cover shows a novel method to synthesize terminal acetals from vinylarenes and diols by palladium‐catalyzed aerobic anti‐Markovnikov oxidation.In their Full Paper, S. Matsumura et al. demonstrate that an electron‐deficient cyclic alkene, i.e. methoxy‐p‐benzoquinone (MeOBQ), is a key additive that accelerates the reaction and affords high yields of the products by reducing the electron density of the palladium center upon coordination. The coordination of MeOBQ would also stabilize in situ generated Pd(0) species to suppress deactivation. [ABSTRACT FROM AUTHOR]