Silver catalysis decarboxylation

The decarboxylative fluorination of a wide range of aliphatic carboxylic acids with Selectfluor is achievable under silver catalysis (Scheme 4.83) [87]. 

O/t/20-arylation of benzoic acids is often preferable to ortho-arylation of benzamides if conversion of the amide moiety to other functional groups is desired. However, only a few reports have dealt with the orf/io-functionalization of free benzoic acids due to challenges that involve such transformations. The reactions can be complicated by decarboxylation of the product and the starting material. Despite those difficulties, several methods for direct o/t/io-arylation of benzoic acids have been developed. Yu has shown that arylboronates are effective in arylation of benzoic acids under palladium catalysis [59], The reactions require the presence of palladium acetate catalyst, silver carbonate oxidant, and benzoquinone. Even more interestingly, the procedure is applicable to the arylation of unactivated sp3 C-H bonds in tertiary carboxylic acids such as pivalic acid (Scheme 13) if aryl iodide coupling partner is used. Aryl trifluoroborates can also be used [60],... 

As a noble metal, silver becomes one of the most important metals in the life of human beings, which has been used as currency and ornaments by humans for thousands of years. Nowadays, silver and its salts have been widely used in photography, electrical equipment, jewelry, as well as transition metal for catalysis in chemistry. In chemical research, silver complexes were usually thought to be low activity and used as either co-catalysts [1, 2] or Lewis acids [3] for decades. In recent years, a wide range of important organic transformation has been catalyzed by silver complexes, including C-H insertion, amination/amidation, fluorination, hydrosilylation, decarboxylation, and so on [4-12]. 

The arylation of polyfluoroarenes has also been achieved with Pd/Ag catalysis (Scheme 22.43a) [61c]. Mechanistic investigations have demonstrated that the Pd-phosphine complex and the silver salts are both involved in the decarboxylation of electron-rich aromatic acids (Scheme 22.43b ... 

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