Recent Advances in Transition Metal Catalyzed Decarboxylative Coupling Reactions of Alkyl Carboxylic Acid

Carboxylic acids are cheap, readily available, easy to store and handle compounds. Since the studies of decarboxylative Heck reaction of aryl carboxylic acids, transition metal-catalyzed decarboxylative coupling reactions have become an interesting research area. Transition metal-catalyzed alkyl coupling plays an important role in the synthesis of nonplanar molecule. Thus, much attention has been paid to the development of transition metal-catalyzed decarboxylative cross-coupling reactions of alkyl carboxylic acids. This review focuses on: (1) the copper-catalyzed decarboxylative coupling reaction between proline derivatives and nucleophilies including terminal alkynes (C-sp3-C-sp), indoles (C-sp3-C-sp2) and nitromethane (C-sp3-C-sp2), the copper-catalyzed decarboxylative aldol reaction of thioester derivatives, the copper-catalyzed decarboxylative Mannich-type reaction; the copper-catalyzed decarboxylative alkynylation of quaternary a-cyano acetate salts; (2) the palladium-caytalyzed decarboxylative couplings of 2-(2-azaaryl)acetates, cyanoacetate, salts, nitrophenyl acetates salts with aryl halides; (3) the silver-catalyzed decarboxylative chlorination, fluorination and alkynylation.