Synthesis and Conformational Analysis of cis, cis-1, 3, 5-Trimethylcy clohexane-1, 3, 5-tricarboxylic Acid
Conversion of 3, 5, 7-trimethyladamantan-1-ol to a hypobromite, fragmentation in situ, and oxidation with KMnO4 generate the lactone, 6, of cis, cis-1, 3, 5-trimethyl-1-(hydroxymethyl)cyclohexane-3, 5-dicarboxylic acid, which can in turn be oxidized by RuO4-HIO4 to cis, cis-1, 3, 5-trimethylcyclohexane-1, 3, 5-tricarboxylic acid (2). From pKa measurements and1H NMR studies, 2 and its mono- and dianions are assigned chair conformations with the functional groups triaxial. The trianion of 2 is assigned the chair conformation with triequatorial carboxylate anions. Conversion of 6 to the lactone, 8, of cis, cis-1, 3, 5-trimethyl-1-formyl-3-(hydroxymethyl)cyclohexane-5-carboxylic acid and 2 to the cyclic anhydride, 11, of cis, cis-1, 3, 5-trimethyl-1-formylcyclohexane-3, 5-dicarboxylic acid by Rosenmund reduction is described. 1981, American Chemical Society. All rights reserved.