Adamantane-1,3-diol

This dry ozonation procedure is a general method for hydrox-ylation of tertiary carbon atoms in saturated compounds (Table 1). The substitution reaction occurs with predominant retention of configuration. Thus cis-decalin gives the cis-l-decalol, whereas cis- and frans-l,4-dimethylcyclohexane afford cis- and trans-1,4-dimethylcyclohexanol, respectively. The amount of epimeric alcohol formed in these ozonation reactions is usually less than 1%. The tertiary alcohols may be further oxidized to diols by repeating the ozonation however, the yields in these reactions are poorer. For instance, 1-adamantanol is oxidized to 1,3-adamantane-diol in 43% yield. Secondary alcohols are converted to the corresponding ketone. This method has been employed for the hydroxylation of tertiary positions in saturated acetates and bromides. 

N HCl resultated in the formation of adamantane-diol 13 as sole product, i.e. in... 

Heating a solution of the syn-exo-diepoxide 74 in 0.5N HCl yielded 61% of N(6)-phenylsulfonyl4 8 -dihydroxy-2 -oxa-6-aza-adamantane (76) as the sole tricyclic compound, which was also characterized as its diacetate 49. Analogous treatment of the anti-epoxide 75 led to a mixture of adamantane-diol 76 (48%) and the isomeric N(7)-phenylsulfonyl-4 l0 -dihydroxy-2-oxa-7-aza-isotwistane (77) (22%). Both diols were also converted to the corresponding diacetates 49 and 78 K... 

As already described in 2.1.5.4. a mixture of N(7)-phenylsulfonyl-4 l0 -dihy-droxy-2-oxa-7-aza isot vistane (77, 22%) and the isomeric adamantane-diol 76 (61%), both compounds also characterized as their acetates 78 and 49 was obtained by refluxing a solution of the anti-diepoxide 75 in 0.5N HCl. 

Fig. 4.2 Oxidation of adamantane to (a) adamant-l-ol (b) adamant-2-ol (c) adamant-1,3-diol (d) adamant-2-one...

The absolute configurations of two rigid cyclic diols, (—)-adamantane-2,6-diol and ( )-spiro[5.5]undecane-3,9-diol, have been determined by the application of the dibenzoate chirality rule to the bis(p-methoxybenzoate) derivatives195,196. 

Oxa-adamantane. Treatment of bieyclo[3.3.l npnane-2,6-diol (1) with 95% fiulfuric acid at room temperature afi ords 2-oxa-adamanlane (2) in 35-40% yield. 

The isomerization of endo-trimethylenenorbomane to the exo isomer is efficiently catalyzed by superacid systems in cyclohexane or Freon-113 (1,1,2-tri-chloro-l,2,2-trifluoroefhane) [65]. The fd (SO,l l-Sbl -, system is also effective for isomerization of trimefhylenenorbornane to adamantane, although a stoichiometric amount of the acid is necessary to obtain good results [66]. SbCl and SbClj-AgSbFg promote the pinacol rearrangement of 1,2-diols and their trimethylsilyl ethers (Scheme 14.27) [67]. 

OxidationIn the presence of ruthenium porphyrin oxo complexes, such as RuTMP02, and a trace of HBr or HCl, pyridine N-oxidc 1 can oxidize alkanes to secondary alcohols at 25° in high yield. The reactive intermediate is not known. Adamantane is oxidized mainly to the 1-hydroxy derivative (68%) adamantanc-l,3-diol (15-25%) and adamantanonc-2 (1-2%) arc minor products. 

Further syn-4,8-disubstituted 2,6-dioxa-adamantanes were prepared from diene 1 applying pathway B by Cuthbertson and MacNicol dibromide 11 14 and by Averina -> dibromide 11, dichloride 12 and diol 13. The latter 13 was... 

Treatment of 4° 8° -dichloro-2-oxa-6-thia-adamantane 24) with aqu. Na2C03-solution yielded almost quantitatively the corresponding diol 25 (episulfonium) ion) (2.1.3.) whereas reaction of 24 with silver oxide in methanol gave the dimethoxy-conmound 27 (episulfomium ion) (2.1.3.) ... 

The unique structure of adamantane justifies the interest for selective functionalization of this molecule in order to develop enhanced functional materials. In particular, selective synthesis of monoalcohols or diols represents the first step for the production of photoresist materials via esterification of the hydroxyl groups with acryUc and methacrylic acids [7]. 

In the initial crystal structure(2E) the C2 and C6 methyl groups were apparently uninvolved in the packing arrangement and therefore the homologues (1) and (3) were the next compounds studied. Both diols adopted totally different close packed structures with no cavities. Likewise the adamantane analogue (4) was found to possess yet another crystal without void spaces. The disparate behaviour of these three compounds, despite their being very closely related in structure to the original diol host (2), provides a clear illustration of the structural subtleties which can be involved in this area. 

A -hydroxyphthalimide, a radical catalyst, has been reported to promote the oxidation of various organic substrates such as diols, alkylbenzenes, cycloalkanes and adamantanes by dioxygen under mild conditions . The oxidation takes place both in the absence and presence of Co(a ac)2 or Co(iu ic)3. 

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