Transition Metal-Catalyzed Carboxylation of Organic Substrates with Carbon Dioxide

Abstract

The development of sustainable chemical processes is a long-standing challenge. Carbon dioxide represents a renewable C1 building block for organic synthesis and industrial applications as an alternative to other common feedstocks which are based on natural gas, petroleum oil, or coal. Apart from the advantages associated with the nontoxicity and abundance of CO 2 , its utilization further enables the reduction in its atmospheric content, which contributes significantly to the greenhouse effect. Although widespread application of CO 2 in organic synthesis -even on an industrial scale -will not be able to fully compensate for the steadily increasing atmospheric quantities produced (mainly by the combustion of fuels), ecological and economical factors make its usage highly desirable. Therefore, tremendous efforts toward activation and utilization of CO 2 have been made by the scientific community over the last 30 years, and, as a result, the number of highly efficient transition metal-catalyzed CO 2 -incorporative reactions has increased dramatically, especially within the last decade. The achievements in the development of sustainable and economic chemical processes for the carboxylation of organic molecules with CO 2 are presented in detail in this chapter.

Palladium-Catalyzed Selective Five-Fold Cascade Arylation of the 12-Vertex Monocarborane Anion by B–H Activation

“…To our surprise, the palladium- and silver-mediated decarboxylation processes all require insurmountable barriers (Figures S17 and S18). Instead, we discovered that deprotonated penta-arylated products can undergo facile decarboxylation without any additional reagent (Table ). With R = Ph ( 3a ), the decarboxylation barrier is only 13.6 kcal/mol, and the reaction is exergonic with Δ G solv = −0.5 kcal/mol (entry 1).…”

The use of carboxylic acids as traceless directing groups for regioselective C–H bond functionalisation

“…In order for monoortho-substituted benzoic acids 28 and less electron rich benzoic acids 29 to undergo decarboxylation a stoichiometric amount of palladium was required (Scheme 6). 26 Mechanistic studies by various groups 14 have shown a very distinct reaction profile for the palladium system compared to those for copper and silver; firstly the decarboxylation proceeds through a 4-membered transition state with no interaction with the carboxyl carbon (see 31 vs. 8 and 19, Scheme 7).…”

Ni- and Fe-catalyzed Carboxylation of Unsaturated Hydrocarbons with CO2

“…While a significant step-forward, such a method is not particularly step-economical and requires handling with stoichiometric and, in many instances, air-sensitive organometallic species, thus reinforcing a change in strategy. Although the recent years have witnessed the discovery of a myriad of elegant catalytic reductive carboxylation techniques with organic (pseudo)halides [13][14][15][16], the utilization of unsaturated hydrocarbon counterparts constitutes an ideal platform in the carboxylation arena, as these motifs can be obtained in bulk from our petrochemical industry, thus representing a formidable and unique opportunity for converting raw materials into valuable products at the industrial level [17]. Additionally, such a scenario would allow for accessing carboxylic acids at a large scale while avoiding the utilization of toxic carbon monoxide [11].…”