Stereochemistry in the hydrogenation of 4-t-butylcyclohexanone and the corresponding oxa- and dioxacyclohexanone was examined. A high cis selectivity was observed in the latter two compounds regardless of the catalyst metals used here. These results were explained in terms of intramolecular n O–π CO interaction, which was supported by 13 C NMR chemical shifts of the carbonyl carbons and CNDO/2 calculation.
