Revisiting the Palladium-Catalyzed Carbonylation of Allyl Alcohol: Mechanistic Insight and Improved Catalytic Efficiency

Although crotonic acid (CA) is in high demand due to its use in various industrial applications, the preparation of CA currently requires a multi-step process from the petrochemical cracking of ethane with a very low overall yield and poor selectivity. An atom economical, one-step, carbonylation of readily accessible allyl alcohol to CA is one of the attractive approaches. In this study, the direct carbonylative transformation of allyl alcohol to CA was analyzed in detail to detect the reaction intermediates and propose a reaction mechanism. Following the reaction mechanism, the process was optimized to synthesize CA via the direct carbonylation of allyl alcohol with improved efficiency and productivity (TON = 420) under mild reaction conditions using Pd-based catalytic systems.