Scope of chemical fixation of carbon dioxide catalyzed by a bifunctional monomeric tungstate

• A simple monomeric tungstate is efficient for chemical fixation of CO2.
• Compound I showed bifunctional activation of both CO2 and nucleophiles.
• Various kinds of nucleophiles could be converted into the corresponding products.

The tungsten-oxo moiety in a simple monomeric tungstate, TBA2[WO4] (I, TBA = tetra-n-butylammonium), showed bifunctional activation of both CO2 and 1,2-phenylenediamine (1a). It was confirmed by 1H, 13C, and 183W NMR spectroscopies that adducts I–1a and I–(CO2)n (n = 1 and 2) were formed by the reactions of I with 1a and CO2, respectively. These adducts played important roles in formation of the corresponding carbamic acid intermediates. The present bifunctionality could be applied to chemical fixation of CO2 even at atmospheric pressure with various kinds of structurally diverse aryl diamines, primary monoamines, propargylic alcohols, and propargylic amines into cyclic urea derivatives, 1,3-disubstituted urea derivatives, cyclic carbonates, and cyclic carbamates, respectively.

Figure optionsDownload high-quality image (96 K)Download as PowerPoint slide