Mechanistic Understanding of Transition-Metal-Catalyzed Olefin Isomerization: Metal-Hydride Insertion-Elimination vs. π-Allyl Pathways

Mechanistic aspects of olefin isomerization through an alkyl chain are discussed in this review. The mechanism primarily has been categorized in two pathways: (1) metal-hydride insertion-elimination pathway; and (2) π-allyl pathway. Different mechanistic features of the two pathways are elaborated here. These features often vary among different reaction systems. Several types of experiments, such as 1,3 or 1,2-H/D exchange, crossover experiments, and other techniques, are explained. The results from different experiments are logically discussed to elucidate the mechanism for olefin isomerization.