A detailed study of the elementary steps leading to the formation of 9 is outside the scope of this publication and will be disclosed in due course. A possible simplified mechanism to account for the formation of the two polyoxygenated fragments is depicted in Scheme 6. In both cases, it would begin with an electrophilic aromatic substitution on the toluene solvent induced by the interaction of the ethynediolate complex 2 with CO2. The acidic proton in the Wheland intermediate is trapped by one Cp ttt ligand, resulting in the release of HCp ttt , which was observed spectroscopically. This first step could therefore be seen as a Friedel-Crafts-type reaction leading to the functionalization of toluene and formation of a deprotonated form of 2,3-dihydroxy-3-(p-tolyl)acrylate. This polyoxygenated intermediate further reacts with one more equivalent of CO2 either at the nucleophilic carbon atom or at the nonconjugated anionic oxygen atom, yielding fragments A or B, respectively. Scheme 6. Suggested mechanism in the formation of 9 leading to the formation of fragments A and B.