Schoenberg A,
Bartoletti I,
Heck RF *.
University of Delaware, Newark, USA
Palladium-Catalyzed Carboalkoxylation of Aryl, Benzyl, and Vinylic Halides.
J. Org. Chem. 1974;
39: 3318-3326
Keywords
carboalkoxylation - carbon monoxide - Heck carbonylation - palladium catalysis
Significance
Two years after the invention of the famous Heck reaction (J. Org. Chem.
1972, 37, 2320), Heck and co-workers reported the palladium-catalyzed alkoxycarbonylation of aryl, benzyl, and vinyl halides with an alcohol under a carbon monoxide atmosphere. This carbonylative coupling is broadly applicable and represents a pivotal transformation for the synthesis of esters.
Comment
Heck and co-workers proposed two possible mechanisms for the palladium-catalyzed alkoxycarbonylation (see scheme). The mixtures of alkene geometries observed in certain cases are likely due to a π-allylic palladium intermediate, which can lead to both Z and E products.
