Decarboxylative/decarbonylative coupling

Scheme 17.31 Decarboxylative/decarbonylative C-H couplings of 2-phenylpyridine with various carbonyl compounds.

Stoner, C.E., Jr., and Brill, T.B. (1989) Thermal Decomposition of Energetic Materials 34. Decarbonylation, Decarboxylation and Coupling Reactions of Metal Propiolate Salts, M[02CC=CH] Inorganic Chemistry, in press. 

Lower reaction temperatures favoured decarboxylation and the formation of coupled products (Rb, Co, Zn salts), while decarbonylation tended to occur at higher temperatures (Na Ni salts). 

Other sources for cross-coupling reactions are aldehydes and carboxylic acids after decarbonylation and decarboxylation, respectively, which can be reacted with aryl halides to form biaryls. The following Experimental Procedure illustrates the potential of this quite atom-economic reaction. In this case, a copper co-catalyst promotes both the decarboxylation and the cross-coupling. 

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