Scalable Palladium-Catalyzed Alkoxycarbonylation of Conjugated Dienes.

The Pd(cod)Cl 2 -catalyzed alkoxycarbonylation of conjugated dienes to β,γ-unsaturated esters was approached by both intramolecular phosphinesulfonate L 1 and intermolecular PPh 3 /PTSA in this study. However, the poor solubility of the Pd/L 1 complex and the labile monodentate Pd/PPh 3 structure restricts the system efficiency, especially for the scale-up application. By contrast, the stable and well-soluble bidentate Xantphos system allows for the quantitative formation of 3-pentenoate (96%) on a gram scale within 6 h in weakly alkaline N -methylpyrrolidone (NMP), which also functions as a basic site to promote the rate-limiting alcoholysis step while reducing the dosage of ligand to a theoretical value.