FACE SELECTION IN REACTIONS OF 5,7-DIAZAADAMANTAN-2-ONE DERIVATIVES - MUTUAL INFLUENCE OF REMOTE SUBSTITUENTS

When one of the nitrogen atoms in 5,7-diazaadamantan-2-one(1) (4) is quaternized, for example, as in 3-O, carbonyl reduction occurs principally at the zu face to give alcohol (E)-6-O, in accord with Cieplak-type transition state hyperconjugation. The ratio in this reduction is somewhat less than in that of the previously reported monoaza N-oxide 2-O, which is attributed to the effect of hyperconjugation in the initial state of 3-O. If the parent diaza ketone 4 is reduced first to the corresponding diaza alcohol 5 and if this is then oxidized to 6-O, the Z-isomer is the principal product. The stereochemistry of this latter reaction is also considered to be a result of extended hyperconjugation. Virtually identical data are obtained with the methyl iodide salts. It is concluded that the effect of remote substituents is mutual and that this fact can be exploited to influence, even reverse, the stereochemical outcome of a synthesis by manipulation of the sequence of the individual steps.