EFFECT OF REMOTE SUBSTITUTION ON FACE SELECTION IN ADDITION-REACTIONSOF NOR-DAMANTAN-9-ONE AND HOMOADAMANTAN-9-ONE AND OF SEVERAL ANALOGS

The effects of 3-halo substitution on face selection in borohydride re ductions of both nor-and homoadamantan-9-ones l-X and 3-X. respectivel y, have been compared with those of 5-halo substitution in the parent 5-haloadamantan-2-ones 2-X, The differences between the product ratios in these three compounds are small, but the selectivity of 2-X is som ewhat larger than that of either of the homologues. This is also true of the corresponding aza-and diazaadamantanones, and of an electrophil ic addition. It is concluded that the approach angle of the reagent is not a sensitive variable in addition reactions of cyclohexanone and i ts derivatives, and that well-aligned antiperiplanar bonds are preferr ed to achieve maximal remote substituent induced selectivities.