Esters of 2,5-multisubstituted-1,3-dioxane-2-carboxylic acid: their conformational analysis and selective hydrolysis

The carbomethoxy group at the C2 position of the 2,5-multisubstituted 1,3-dioxanes prefers the axial conformation rather than the equatorial one due to an anomeric effect. The trans isomers of the 5-monosubstituted compounds are more selectively hydrolyzed than the cis isomers. Based on the calculated results, hydrolysis to the trans isomers is attributed to the larger carbonyl charges of the trans than those of the cis isomers. The anomeric and homoanomeric effects will explain the axial preference of the carbomethoxy group and selective hydrolysis to the trans isomers. Furthermore, the calculated stability between the cis and trans isomers is in good agreement with the experimental results in the equilibrium state.