Alkenes are desirable and highly versatile starting materials for organic transformations, and well-known substrates for palladium catalysis. Typically, these reactions result in the formation of a new alkene product via β-hydride elimination. In contrast to this scenario, our laboratory has been involved in the development of alkene hydro- and difunctionalization reactions, where β-hydride elimination can be controlled. We report herein the development of an asymmetric palladium-catalyzed hydroarylation, which yields diarylmethine products in up to 75% ee. Interestingly, a linear free energy relationship is observed between the steric bulk of the ligand within a certain range and the enantiomeric excess of the reaction.

A hydrochlorination reaction of styrenes catalyzed by Pd(II) in combination with Cu(II) was developed, which was followed by an in situ conversion of electron-rich products to an ether in the presence of an alcohol. Mechanistic experiments indicate that olefin functionalization is coupled to an alcohol oxidation, wherein a Pd hydride formed in the β-hydride elimination step of the alcohol oxidation was incorporated into the product.

An overview of oxidative reactions promoted by N-heterocyclic carbene (NHC) metal complexes is presented. Rather than attempting to provide a comprehensive review, key systems and recent developments are laid out, with special attention given to mechanistic aspects. Specifically, O2 activation by metal carbene complexes is covered, followed by alcohol oxidation, Wacker-type reactions and oxidative cleavage of alkenes, and alkane as well as arene oxidations proceeding via C–H activation.

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