Abstract Stable carbenes derived from thiazole, 1H-imidazole, and 4H-1, 2, 4-triazole are efficient catalysts for benzointype condensations of formaldehyde. Catalysts derived from N- substituted thiazolium salts trimerize formaldehyde to dihydroxyacetone (II). Catalysts based on 1, 4-disubstituted 4H-1, 2, 4-triazol-1-ium salts give glycolaldehyde (I) as the main product and no II, whereas N, N′-disubstituted 1H-imidazol-3-ium salts yield mixtures of ...
