Carboxylation of 2-methylbutyn-3-ol-2 on Ag- and Cu-containing catalysts

The analysis of the products of direct carboxylation of 2-methylbutyn-3-ol-2 with carbon dioxide on Ag- and Cu-containing catalysts by 1Н and 13С NMR and FTIR spectroscopy showed that the desired 4-hydroxy-4-methylpent-2-ynoic acid did not form under the given conditions; instead, the triple bond of the substrate decomposed, and two polyfunctional acids formed: 4-hydroxy-4-methyl-3-oxopentanoic and 3,4-dihydroxy-4-methylpent-2-enic (the latter is the result of the keto-enol rearrangement of the former keto acid).