Stereochemical peculiarities of the catalytic reduction of sym-octahydrothioxanthylium salts

The three-dimensional structures of the products of catalytic hydrogenation of sym-octahydrothioxanthylium salts in the presence of palladium on carbon were studied by 13C NMR spectroscopy. It was shown that the reaction proceeds stereoselectively with the formation of cis-syn-cis isomers. The stereochemistry of the reduction products is in agreement with the previously proposed reaction mechanism.