Electrocarboxylation of Alkynes with Carbon Dioxide in the Presence of Metal Salt Catalysts

Abstract

With some common metal salts (CuI, FeCl 3 ) as catalysts, alkynes can be effectively electrocarboxylated with CO 2 (4 MPa) in an undivided cell with Ni cathode and Al sacrificial anode containing n-Bu 4 NBr-DMF as supporting electrolyte with a constant current at room temperature. The saturated tricarboxylic acids besides the dicarboxylic acids were obtained in good yields. The yields of the tricarboxylic acids were strongly influenced by various metal salt catalysts, cathode materials and the property of substituted groups. Finally, the possible electrochemical mechanism was discussed.

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

“…The selectivity towards the dicarboxylation product can be significantly increased by working at higher CO 2 pressures [ 61 , 66 ], although an optimum must be found to minimize oxalic acid formation at high CO 2 pressures by electrodimerization of CO 2 [ 72 ]. Under rigorously anhydrous conditions, the dicarboxylation product of alkynes, shown in Scheme 9 , can be transformed to a maleic anhydride [ 61 – 62 ]. Alkynes are rather reactive as such; olefins can be rendered more reactive by introduction of electron withdrawing groups [ 68 – 71 73 – 74 ].…”

Electrochemical dicarboxylation of conjugated fatty acids as an efficient valorization of carbon dioxide

“…23 Another approach, investigated in this work, is the fixation of CO 2 in organic chemicals by means of an energy-efficient one-electron reduction step to produce carboxylic acids, which are important intermediates in the synthesis of polymers and pharmaceuticals. Carbon dioxide has been incorporated in organic compounds such as arylalkenes, [24][25][26][27][28][29][30][31] alkynes, 24,[32][33][34][35][36][37][38] aromatic ketones, [39][40][41][42][43][44] halides [45][46][47][48][49][50] and epoxides. [51][52][53] The electrochemical carboxylation of conjugated dienes has been investigated in less detail, 24,28,[54][55][56][57][58][59][60] with only one paper reporting on the use of an acyclic aliphatic internal conjugated a University of Leuven, Centre for Surface Chemistry and Catalysis, Department of diene as reactant, 56 and most emphasis being paid to the dicarboxylation of butadiene.…”

Translating Tactics from Direct CO2 Electroreduction to Electroorganic Coupling Reactions with CO2

“…[ 30–32 ] The outcome of EC of alkynes depends on the structure of the organic substrate and reaction conditions: the formation of propionic acid derivatives was reported for terminal alkynes at Ag cathodes, [ 33 ] whereas EC of alkynes in the presence of a cocatalyst led to the formation of di‐ and tricarboxylation products in a form of anhydrides. [ 34 ] Besides alkenes and alkynes, the unsaturated bonds of polycyclic arenes can participate in EC, leading to breaking of the aromatic structure and the formation of corresponding dicarboxylic acids. [ 34 ] In addition to the unsaturated CC bonds and CX bonds (X = O and N), double bonds of aromatic ketones [ 35–38 ] and imines [ 39 ] can also be carboxylated with the formation of α‐hydroxy and α‐aminocarboxylic acids.…”

“…[ 34 ] Besides alkenes and alkynes, the unsaturated bonds of polycyclic arenes can participate in EC, leading to breaking of the aromatic structure and the formation of corresponding dicarboxylic acids. [ 34 ] In addition to the unsaturated CC bonds and CX bonds (X = O and N), double bonds of aromatic ketones [ 35–38 ] and imines [ 39 ] can also be carboxylated with the formation of α‐hydroxy and α‐aminocarboxylic acids. Notably, EC of aliphatic ketones does not yield the addition product and result in β‐oxocarboxylic acids as a major product instead.…”