2-Adamantyl acetate

Substituted adamantanes have been employed in the study of several reaction mechanisms. The Kolbe electrolyses of 1- and 2-adamantane carboxylic acids and 1- and 2-adamantyl acetic acids have been compared in detail. Car-bonium ion-derived products are observed from the electrolyses of both 1-adamantyl carboxylic acid and 1-adamantyl acetic acid. A mixture of radical and carbonium ion-derived products are obtained from 2-adamantyl carboxylic acid and mainly radical-derived products are obtained from 2-adamantyl acetic acid. These results parallel the known or expected stabilities of the intermediate carbonium ions 366 ... 

Raney Ni,Al-alloy added during 1 hr. at 85° to a stirred suspension of adaman-tylideneacetic acid in aq. NaOH with spraying of amyl alcohol to diminish foam formation, and stirring continued 1 hr. (2-adamantyl)acetic acid. Y 98.5%. J.Scharp, H.Wynberg, and J. Strating, R. 89, 18 (1970). 

Efficient 1,3-hydrogen rearrangement is also observed in the aceto-lysis of unsaturated brosylate 129 201). This particular case is significant since acetolysis of the closely related tricyclic brosylate 130-OBs produces only a small amount of 2-adamantyl acetate (131), the product of 1,3-hydrogen rearrangement. It is, therefore, evident that the solvolyses of 129 and 130-OBs, do not, for the most part, have a common intermediate. 

The 1-adamantyl cation is also trapped by 1,1-dichloroethylene1921 and 1,1,3-trichloroethylene 193> to give 1-adamantyl acetic acid (Eq. (56)) and archloro- 1-adamantyl acetic acid (Eq. (57)), respectively, after hydrolysis, and by olefins in the presence of hydride donors such as hexane to give alkyl... 

In the electrolysis of l-(adamantyl)acetic acid in alcohols the only products isolated were the 3-homoadamantyl ethers, possibly formed via the cyclopropenyl cation intermediates (77). The same result in methanol was published by a Russian group ... 

Oxidation of n-alkanes by Co acetate in acetic acid occurs with a remarkable regioselectivity (rs) at the alkyl acetate as the major product in anaerobic conditions, and 2-alkanone in the presence of oxygen (equations 233 and 234). Cyclohexane is readily oxidized in nitrogen by Co(OAc)3 in acetic acid to mainly cyclohexyl acetate and 2-acetoxycyclo-hexanone. In the presence of oxygen and a high cobalt concentration, adipic acid is the major product formed (equation 235). Oxidation of adamantane by Co(OAc)s and TFA in AcOH preferentially occurs at the tertiary positions, producing 1-adamantyl acetate as the major product. ... 

B - are obtained by reaction of 0- or room temperature." t I , catalysis the Strecker-type r. "e carried out either in organic, 7... .vomplished using acetals. c. of Sc(OTf)j in the direct t -lation of 1-adamantyl acetate ipt -. are. When using DMAP and X -. .vceeds at room temperature. cethe backward hydrolysis by... 

Many carbamates have been used as protective groups. They are arranged in this chapter in order of increasing complexity of stmcture. The most useful compounds do not necessarily have the simplest stmctures, but are /-butyl (BOC), readily cleaved by acidic hydrolysis benzyl (Cbz or Z), cleaved by catalytic hy-drogenolysis 2,4-dichlorobenzyl, stable to the acid-catalyzed hydrolysis of benzyl and /-butyl carbamates 2-(biphenylyl)isopropyl, cleaved more easily than /-butyl carbamate by dilute acetic acid 9-fluorenylmethyl, cleaved by /3-elimination with base isonicotinyl, cleaved by reduction with zinc in acetic acid 1-adamantyl, readily cleaved by trifluoroacetic acid and ally], readily cleaved by Pd-catalyzed isomerisation. 

Protoadamantanone has been prepared by the nitrous acid deamination of 2-amino-l-adamantanol (77%), by aprotic diazo-tization of endo-7-aminomethylbicyclo[3.3.1]nonan-3-one in benzene with an equivalent amount of acetic acid (67%), and by thermolysis of 1-adamantyl hypohalites followed by base-promoted cyclization of the resulting halo ketones (32-37%)." In spite of low and erratic yields, the last reaction sequence has provided the most convenient route to the protoadamantanes, since the other two approaches require lengthy syntheses of the starting materials. 

Fig. 9 Comparison of polar and steric effects of alkyl groups on bromination rates of linear ( ), branched (O) and adamantyl (A) alkenes in acetic acid and in methanol (Ruasse and Zhang, 1984 Ruasse et al., 1990). Polar effects are identical in both solvents [full line, eq. (24)], but steric effects differ. Deviations of branched alkenes are attributed to steric inhibition of nucleophilic solvation by methanol.

Song and co-workers have taken a variety of aldehydes 344 and treated them with A -adamantyl carbene 1 and trimethylsilyl ketene acetal 345 to produce Mukaiyama aldol products 346 in good yield (Eq. 34) [170], The carbene presumably acts as a Lewis base to activate the silicon - oxygen bond in order to promote reactivity of the enol silane. The catalyst loading can be reduced to as low as 0.05 mol% without a change in yield. 

Manganese(III) acetate is poorly reactive with saturated hydrocarbons.514 However, oxidation of adamantane by Mn(OAc)3 in trifluoroacetic acid gives relatively high yields of 1-adamantyl trifluoroacetate, showing a preferential attack at tertiary C—H bonds.515 Oxidation of n-alkanes by air in the presence of manganese catalysts constitutes the basis for an industrial process for the manufacture of synthetic fatty acids from n-alkanes of petroleum origin, which has been commercially developed in the Soviet Union.516... 

Competition experiments have been carried out to determine the relative reactivities of 23 alkyl chlorides toward allyltrimethylsilane in the presence of ZnCh. The kre scale has been found to span 11 orders of magnitude from the least reactive 1-adamantyl chloride to the most reactive bis(p-methoxyphenyl)methyl chloride384. By contrast, analogous acetals RCH(OMe)2 exhibited very little differences in reactivity385. 

Possibly this is due to a greater charge development in the transition states of the chromyl acetate oxidations. Solvolysis reactions at the 10-position are known to be highly unfavorable 9S). The solvolytic reactivity of 10-tricyclo [5.2.1.0 4>10] decyl tosylate is retarded relative to 1-adamantyl tosylate by a factor of approximately 106 at 70°C in acetic acid. 

As indicated previously (see Eq. (31)), 1-adamantylcarbinyl tosylate sol-volyzes in buffered anhydrous acetic acid to give 3-homoadamantyl acetate (93 %) and 1-adamantylcarbinyl acetate (7 %) 96). The acetolysis of chiral 1-adamantyl-l -d tosylate (103) has been found to occur with complete retention of configuration in both products (Eq. (80)) 97>. This result suggests... 

To a mixture of 1-bromoadamantane (0.3 mmol), TPDS (0.45 mmol), and caffeine salt (1.5 mmol) with camphorsulfonic acid was added AIBN (0.45 mmol) over 8 h (5 times in 2 h intervals). After 4 h, TPDS (0.45 mmol) was added again. After a total of 22 h, sat. aq. NaHC03 solution was added and the mixture was extracted with ethyl acetate. The organic layer was dried over Na2S04. After removal of the solvent, the residue was chromatographed on silica gel to provide 2-(l-adamantyl)caffeine in 55% yield [30]. 

The above refinements of the interpretation of earlier work have been brought about by two important developments, recognition from studies in trifluoroacetic acid that acetic and formic acids are nucleophilic (Peterson et al., 1965) and the use of 2-adamantyl tosylate as a reference point for SnI reactivity (Schleyer et al., 1970). These developments have led to sensitive ways of detecting nucleophilic assistance and have shown that solvolyses of secondary substrates in acetic and formic acids may be significantly nucleophilically assisted (Table 2). Previous arguments were based on less sensitive tests such as the rate-accelerating effect of low concentrations of added nucleophiles, which must be appropriately oriented and desolvated before they are able nucleophilically to assist in the displacement reaction (Peterson et al., 1967). 

The entire Step 1 product was mixed with 4-dimethylaminopyridine and 239 g of methanol and then refluxed 20 hours. After cooling the mixture was neutralized with glacial acetic acid (0.133 mol) and precipitated in water. The precipitate was dissolved in acetone and then re-precipitated in water, the process being repeated three times. The precipitate was dried, and 102.8 g of polymer product were isolated, consisting of 70% p-hydroxystyrene and 30% 2-ethyl-2-adamantyl methacrylate with a of 8200 daltons and polydispersity of 1.68. 

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