CH Carboxylation of Terminal Alkynes Catalyzed by Low Loadings of Silver(I)/DMSO at Ambient CO₂ Pressure

Silver tungstate: a single-component bifunctional catalyst for carboxylation of terminal alkynes with CO2 in ambient conditions

“…16 Subsequently, several silver salts were investigated. Most of the tested silver compounds exhibited poor to moderate activity without any additive at room temperature (entries [6][7][8][9][10][11][12][13][14]. Interestingly, when Na 2 WO 4 was added to the AgNO 3 -catalyzed system, the yield of 2a dramatically improved from 54% to 72%.…”

“…For 1,4-diethynylbenzene, biscarboxylative product 2ja was formed as the major product with 64% yield and 24% yield of the monocarboxylative product 2jb, which was also detected (entry 10). Aliphatic alkynes (entry 11) and heteroaromatic acetylenes (entries [12][13][14][15] were also found to be suitable substrates. In agreement with the DFT calculation, 3-ethynylpyridine showed lower activity when compared with 2-ethynylpyridine (entry 12 vs. 13), indicating that the acidity of the alkyne proton strongly impacts on the activity.…”

Making C–C Bonds from Carbon Dioxide via Transition-Metal Catalysis

“…These observations suggest that strong coordination between the electron-rich metal center and ligand activates the CO 2 Terminal alkynes display relatively acidic C-H bonds (pK a * 25) and can undergo carboxylation at elevated temperatures and pressures [40,41]. In the presence of a catalyst [58], mild carboxylations have been reported with copper and silver salts, both with [59][60][61] and without [62][63][64][65] external halide reagents to trap the formed carboxylate ( Fig. 6).…”

Transition Metal-Catalyzed Carboxylation of Organic Substrates with Carbon Dioxide

“…Shortly after Zhang and Lu had disclosed the carboxylation of terminal alkynes using AgI, Gooßen was able to improve on this procedure significantly by simply using DMSO as solvent [106]. Thus, at very low catalyst loading of Ag(I) sources such as AgBF 4 or Ag 2 O (500 ppm) and 1 bar of CO 2 , various 1-alkynes were converted to propiolic acids in very high yields, with only a few exceptions.…”