FACE SELECTION IN THE REDUCTION OF P,P'-DISUBSTITUTED 5,7-DIPHENYL-2-ADAMANTANONES AND HYDROLYSIS OF THE CORRESPONDING 2-ADAMANTYL TOSYLATES

The reduction of 5,7-diphenyl-2-adamantanone with sodium borohydride i n 2-propanol is affected by the introduction of a p-nitro substituent in one of the rings: the E-alcohol is obtained in small but easily mea surable excess of 1.30:1. Conversely, the introduction of a p-amino gr oup leads to an excess of Z-isomer by roughly the same factor (1.28). When both substituents are present, they evidently cooperate to produc e a ratio of 1.64. The tosylates of the alcohols were prepared and the ir solvolysis rates measured in 3% aqueous hexafluoro-2-propanol and c ompared with those of the parent and p-substituted 5-phenyl-2-adamanty l tosylates. Additivity of substituent effects was again observed, but the p-aminophenyl group in these reactions was deactivating compared to phenyl, presumably due to II-bonding and/or protonation of the amin o group in the acidic medium.