Abstract
The reaction of cyclobutane-1,2-dione with hydroxide was studied by a variety of ab initio (MP2, SCS-MP2, CCSD(T), CEPA/1) and density functional (M06-2X) methods. Three possible reaction paths of the initially formed tetrahedral adduct leading to either 1-hydroxycyclopropane-1-carboxylate (benzilic acid type rearrangement, path A), α-oxobutanoate (path B) or γ-oxobutanoate (path C) were considered. Although the latter two products show similar or even more negative Gibbs free energies of reaction than calculated for the benzilic acid type rearrangement, the Gibbs free energies of activation are substantially higher. According to the calculations, the only feasible reaction appears to be the formation of 1-hydroxycyclopropane-1-carboxylate, which is corroborated by previous experimental observations.
Highlights
E.g., OH, to 1,2-dicarbonyl compounds leads to the formation of relatively stable tetrahedral adducts (Scheme 1) [1]
These adducts further react either by (i) fission of the R2–C bond and migration of R2; (ii) fission of the R2–C bond without migration of R2 resulting in α-oxocarboxylic acids; or (iii) fission of the carbonyl-C–sp3-C with formation of an aldehyde and carboxylic acid
In nucleophilic addition reactions to carbonyl compounds in aqueous solution, water acts as a solvent but frequently actively participates in the reaction, such as in water-assisted hydrolysis [16,17,18,19,20] or in the benzil–benzilic acid rearrangement [11]
Summary
E.g., OH–, to 1,2-dicarbonyl compounds leads to the formation of relatively stable tetrahedral adducts (Scheme 1) [1]. These adducts further react either by (i) fission of the R2–C bond and migration of R2 (benzil–benzilic acid rearrangement, path A); (ii) fission of the R2–C bond without migration of R2 resulting in α-oxocarboxylic acids (path B); or (iii) fission of the carbonyl-C–sp3-C with formation of an aldehyde and carboxylic acid (path C). We present a detailed computational study (DFT and ab initio) of the base-catalyzed reactions of cyclobutane-1,2-dione (1) taking into account all three possible pathways
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
