N-heterocyclic Carbene Copper-Catalyzed Carboxylation of Alkynes with Carbon Dioxide

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dc.contributor Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta fi
dc.contributor University of Helsinki, Faculty of Science en
dc.contributor Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten sv
dc.contributor.author Hiltunen, Otto-Matti
dc.date.issued 2020
dc.identifier.uri URN:NBN:fi:hulib-202003161557
dc.identifier.uri http://hdl.handle.net/10138/313405
dc.description.abstract Copper complexes are versatile catalysts for different fixations of carbon dioxide. Copper-catalyzed carboxylations of unsaturated hydrocarbons with CO2 provide access to valuable carboxylic acids. Generally, the formation of Cu-C species from the substrate and the catalyst is followed by carbon dioxide insertion across the Cu-C bond which produces copper carboxylate RCOO-Cu via C-C bond formation. Moreover, copper complexes can undergo transmetallation with less-nucleophilic organoboron reagents to afford Cu-C species. Copper-catalyzed reductive carboxylations of C-C unsaturated bonds with CO2 entail hydrogenative, alkylative and heterocarboxylation methodologies. This thesis elaborates a protocol for the N-heterocyclic carbene copper (I)-catalyzed synthesis of carboxylic acids from alkynes with carbon dioxide. The main interest lies in a regioselective hydrocarboxylation of alkynes catalyzed by NHC-copper hydrides and copper-catalyzed carboxylation of alkylboranes with CO2. The literature review focuses on the catalytic activity of N-heterocyclic copper (I) complexes in organometallic chemistry, especially within a range of reductive carboxylation reactions. Alkynes insert readily into the copper hydride bond constituting C-Cu species prior to the CO2 insertion. The regioselectivity of this carboxylation reaction derives from the syn addition of Cu-H species to the alkyne. Correspondingly, the alkylboranes can be carboxylized in a regiospecific fashion due to the regioselective manner of the initial hydroboration. In the experimental part, two different catalytic hydrocarboxylation pathways were carried out with in situ- copper (I) catalysts. The use of mild base additive CsF was necessary for the catalyst formation. The first pathway was catalyzed by a NHC-copper(I)-hydride complex in the presence of hydrosilane as the reducing agent. In the second pathway, a tandem hydroboration carboxylation sequence was utilized, catalyzed by copper(I) fluoride species. Both pathways furnished carboxylic acids from terminal and internal alkynes. en
dc.language.iso eng
dc.publisher Helsingin yliopisto fi
dc.publisher University of Helsinki en
dc.publisher Helsingfors universitet sv
dc.title N-heterocyclic Carbene Copper-Catalyzed Carboxylation of Alkynes with Carbon Dioxide en
dc.type.ontasot pro gradu -tutkielmat fi
dc.type.ontasot master's thesis en
dc.type.ontasot pro gradu-avhandlingar sv
dc.subject.discipline none und
dct.identifier.urn URN:NBN:fi:hulib-202003161557
dc.subject.specialization ei opintosuuntaa fi
dc.subject.specialization no specialization en
dc.subject.specialization ingen studieinriktning sv
dc.subject.degreeprogram Kemian ja molekyylitieteiden maisteriohjelma fi
dc.subject.degreeprogram Master's Programme in Chemistry and Molecular Sciences en
dc.subject.degreeprogram Magisterprogrammet i kemi och molekylära vetenskaper sv

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