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Effect of Remote Substitution on Face Selection in Addition Reactions of Nor- and Homoadamantan-9-ones and of Several Analogues

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journal contribution
posted on 18.04.1998, 00:00 by Mira Kaselj, Elena M. Gonikberg, William J. le Noble
The effects of 3-halo substitution on face selection in borohydride reductions of both nor- and homoadamantan-9-ones 1-X and 3-X, respectively, 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 somewhat larger than that of either of the homologues. This is also true of the corresponding aza- and diazaadamantanones, and of an electrophilic addition. It is concluded that the approach angle of the reagent is not a sensitive variable in addition reactions of cyclohexanone and its derivatives, and that well-aligned antiperiplanar bonds are preferred to achieve maximal remote substituent induced selectivities.