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Free keywords:
carboxylic acids; catalysis; palladium; Heck reaction; di-tert- butyl dicarbonate
Abstract:
The first protocol for a direct Heck olefination of aromatic carboxylic acids has been developed. By treatment with commercially available di-tert-butyl dicarbonate, the carboxylic acids are converted in situ into the mixed anhydrides, which in the presence of a palladium catalyst react with olefins to give styrene derivatives. As by-products, only volatile CO and CO2, along with tert-butanol are formed, making the work-up of the reaction products particuarly easy. A mixture of PdCl2, LiCl and gamma-picoline was identified to be the most effective catalyst system.
