Regio- and Stereoselective Synthesis of 2,3,5-Trienoates by Palladium-Catalyzed Alkoxycarbonylation of Conjugated Enyne Carbonates

Palladium-catalyzed carbonylation of 2,4-enyne carbonates in an alcohol and under balloon pressure of CO proceeds through 1,5-substitution to yield (E)-2,3,5-trienoates The olefin geometry of the substrate is important to control the overall stereochemistry of this alkoxycarbonylation method. The reation proceeds through successive formation of pi-allylpalladium with an R-3 group oriented syn and sigma-allenyl palladium complexes.