90-27-7Relevant articles and documents
Park,Wright
, p. 3036 (1954)
Mechanistic Insights into Copper-Catalyzed Carboxylations
Obst, Marc F.,Gevorgyan, Ashot,Bayer, Annette,Hopmann, Kathrin H.
, p. 1545 - 1552 (2020)
The copper-NHC-catalyzed carboxylation of organoboranes with CO2 was investigated using computational and experimental methods. The DFT and DLPNO-CCSD(T) results indicate that nonbenzylic substrates are converted via an inner-sphere carboxylation of an organocopper intermediate, whereas benzylic substrates may simultaneously proceed along both inner-and outer-sphere CO2 insertion pathways. Interestingly, the computations predict that two conceptually different carboxylation mechanisms are possible for benzylic organoboranes, one being copper-catalyzed and one being mediated by the reaction additive CsF. Our experimental evaluation of the computed reactions confirms that carboxylation of nonbenzylic substrates requires copper catalysis, whereas benzylic substrates can be carboxylated with and without copper.
Mechanistic Investigation of the Nickel-Catalyzed Carbonylation of Alcohols
Comba, Peter,Ghosh, Tamal,Hashmi, A. Stephen K.,Krieg, Saskia,Menche, Maximilian,Paciello, Rocco,Rück, Katharina S. L.,Sabater, Sara,Sch?fer, Ansgar,Schaub, Thomas
supporting information, (2020/03/19)
The carbonylation of alcohols represents a straightforward and atom-efficient methodology for the preparation of carboxylic acids. It is desirable to perform these reactions under precious metal-free and low-pressure conditions, with regioselectivity control. In this work, we present a detailed mechanistic study of a catalytic system based on NiI2, which can carbonylate benzylic alcohols in a highly regioselective manner to the corresponding branched carboxylic acids, core motifs for nonsteroidal drugs. The combination of catalytic amounts of nickel and iodide is crucial for efficient catalytic and regioselective conversion. Quantum-chemical computations were used to evaluate the underlying mechanistic processes. They revealed that a combination of two mechanisms is responsible for the observed reactivity and that the oxidative addition of alkyl halides to the Ni(0) species follows a radical oxidation pathway via two one-electron steps.
Exploration of New Biomass-Derived Solvents: Application to Carboxylation Reactions
Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
, p. 2080 - 2088 (2020/02/20)
A range of hitherto unexplored biomass-derived chemicals have been evaluated as new sustainable solvents for a large variety of CO2-based carboxylation reactions. Known biomass-derived solvents (biosolvents) are also included in the study and the results are compared with commonly used solvents for the reactions. Biosolvents can be efficiently applied in a variety of carboxylation reactions, such as Cu-catalyzed carboxylation of organoboranes and organoboronates, metal-catalyzed hydrocarboxylation, borocarboxylation, and other related reactions. For many of these reactions, the use of biosolvents provides comparable or better yields than the commonly used solvents. The best biosolvents identified are the so far unexplored candidates isosorbide dimethyl ether, acetaldehyde diethyl acetal, rose oxide, and eucalyptol, alongside the known biosolvent 2-methyltetrahydrofuran. This strategy was used for the synthesis of the commercial drugs Fenoprofen and Flurbiprofen.
