Decarboxylative coupling reactions: a modern strategy for C–C-bond formation

Abstract

This critical review examines transition metal-catalyzed decarboxylative couplings that have emerged within recent years as a powerful strategy to form carbon-carbon or carbon-heteroatom bonds starting from carboxylic acids. In these reactions, C-C bonds to carboxylate groups are cleaved, and in their place, new carbon-carbon bonds are formed. Decarboxylative cross-couplings constitute advantageous alternatives to traditional cross-coupling or addition reactions involving preformed organometallic reagents. Decarboxylative reaction variants are also known for Heck reactions, direct arylation processes, and carbon-heteroatom bond forming reactions.

A decarboxylative approach for regioselective hydroarylation of alkynes

“…Ruthenium catalysts have been explored rarely as promoters of the decarboxylation of benzoic acids 47 . A major challenge was to achieve high chemoselectivity to promote hydroarylation product 3a over multiple by-products from reported coupling reactions, which include alkyne hydrocarboxylation (4a) 29 , oxidative [4+2] heterocyclization (5a) 48 and oxidative [2+2+2] carbocyclization via decarboxylation (6a) 35 . To this end, we evaluated a wide range of reaction parameters, such as ruthenium catalyst precursor, ligand, salt additive, solvent and reaction temperature.…”

“…The carboxyl functionality could serve as an ortho-directing group that would be removed by metal-mediated decarboxylation after C-H alkenylation and give products with the vinyl group meta or para to the remaining substituents (Fig. 1d) [26][27][28][29][30] . This decarboxylative approach to alkyne hydroarylation would use ubiquitous benzoic acids as easily accessible aromatic building blocks, with CO 2 as the only by-product and no salt waste.…”

“…However, catalytic decarboxylation of benzoic acid derivatives is typically slow and generally requires ortho-substitution of σ-electronwithdrawing or sterically hindered groups for substrate activation 31 . The vast majority of such decarboxylative transformations also require high reaction temperatures, often above 140°C, which thus significantly limits the substrate scope [27][28][29][30][31] . To achieve satisfactory reactivity, many decarboxylation processes also utilize stoichiometric silver(I) or copper(II) salts that further limit the compatibility with oxidation-sensitive functional groups, although significant progress has been made by Gooβen and co-workers to reduce the amounts of these salt additives 27,[32][33][34] .…”

Palladium‐Catalyzed Decarbonylative Trifluoromethylation of Acid Fluorides

“…Encouragingly, acid fluorides have previously been coupled to give the corresponding ketones under metal catalysis, as pioneered by Rovis 11. However, while the decarbonylation of carboxylic acids and their derivatives1m,1o, 12 (including acid chlorides13) has been widely studied, to date, there has been no report of a successful decarbonylation of acid fluorides.…”

Synthesis of Phenanthridinone Derivatives by Direct Arylation. Characterization of the Absorption and Emission Spectra for Representative Examples

“…A reação de Suzuki-Miyaura aplicada à síntese de derivados de 1 mostra a versatilidade desta metodologia para o acoplamento de substratos altamente funcionalizados, apesar da necessidade de utilizar dois reagentes pré-funcionalizados para a síntese da ligação biarila (Figura 2, F). 64 Ácidos benzóicos podem substituir ácidos fenil borônicos em reações de acoplamento cruzado, 65 e um exemplo aplicado à síntese de 1 envolveu o aquecimento do ácido N-2-bromobenzoil-N-metilantranílico em NMP na presença de Pd(OAc) 2 .…”