Oxidation adamantane

When the reaction mechanism is probed for adamantane oxidation, concordant information is obtained. For random attack on the 12 and 4 H atoms belonging to secondary (C2) and tertiary (C3) C atoms, respectively, a C3/C2 ratio of 0.33 should be obtained. For radical reactions, values as high as 20 have been reported due to the higher reactivity of tertiary C-H bonds, while for pure oxo chemistry reduced ratios as low as 3 were determined. With FenY and Fe(bpch)Y, the respective ratios of 20 and 3.6 point to the predominant occurrence of radical and oxo chemisty, respectively. 

The kinetics of decomposition of the DMDO lb have been studied in the reaction of adamantane oxidation both in the presence and in the absence of CClsBr <1996TL249>. The authors found that in the abscence of CClsBr the... 

The reaction mechanism is studied in batch-reactors for adamantane oxidation (table 7) in dichloromethane, as the solubility of adamantane in MeCN is very low. An 80% tBHP solution in ditertbutylhydroperoxide is used as oxidant to circumvent possible phase separation. For the HPTP / Fe complex adamantan-l-ol is a major oxidation product. For HPTP / Fe / MMT adamantanyl-tbutyl-peroxide is observed and seems stabilised on the clay. Both the homogeous and MMT supported reaction show relative reactivities of the secondary and the tertiary C-atoms in adamantane which are close to these of radical reactions. 

Adamantane and cis-decalm were hydroxylated with high selectivity, complete stereo-retention, extraordinarily high rates (up to 800 turnovers min ), and high efficiency with up to 15,000 turnovers. Similar conversions were obtained when Ru(VI)(TPFPP)(0)2 and Ru(VI)(TPFPBr8P)(0)2 were used as catalysts. Oxygenation of less reactive substrates such as benzene and cyclohexane proceeded with lower but still significant turnover numbers (100-3,000). Tertiary vs secondary selectivity in adamantane oxidation was above 210. No rearrangement products were detected in cw-decalin hydroxylation. 

Addition of dianisyl telluride (Tn Te) to the Gif IV system increases the yield of secondary alcohol in adamantane oxidation [141],... 

Apart from the relatively slow reactions of TBHP, the kinetic isotope effect for c> clohexane versus perdeuterocyclohexane is at room temperature about 8 (44).3). This value differs markedly from tlie corresponding value for H2O2 which is 2.2 ( 0.1). Also, the selectivity for adamantane oxidation is different having C /C about 0.5. 

A marginally catalytic oxidation of cyclohexane using a Ru(OEP)(PPh3)Br/PhIO system was mentioned above (Section 3.3.). The Ru(TMP)(0)2 species is thermally unreactive toward cyclooctane at 1 atm O2 at 70°C, but some O-atom insertion into saturated C-H bonds has been achieved under photolytic conditions and with the electrochemically generated Ru(TMP XOX species few details are available, but the latter system showed for adamantane oxidation the usual radical selectivity (tertiary > secondary carbon). 

Although it is not a reaction of alkenes, oxidation of some alkanes with Pd(ll) is cited here. 1-Adamantyl Irilluoroacetate (155) was obtained in above 50% yield by the reaction of adamantane with Pd(OAc)2 in trifluoroa-cetic acid at 80 C[171]. 

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. 

Adamantanol has been prepared by oxidation of adamantane with peroxyacetic acetic" and by hydrolysis of 1-bromoadamantane with silver nitrate s or hydrochloric acid. ... 

Dimerization and condensation of pentane-2,4-dione by molybdenum(VI) oxide tetrachloride (MoOC14) affords l,3,5,7-tetramethyl-2,4,6,8-tetraoxa-adamantane, the structure of which is determined by elemental analysis, IR, mass, and PMR spectroscopy.188... 

Face selectivity in the 1,3-dipolar cycloaddition reactions of benzonitrile oxide and its p-substituted derivatives with 5-substituted adamantane-2-thiones,... 

The ruthenium-substituted sandwich-type POM WZnRu2(OH)(H20)(A W9034)2]11 (X- Zn2+ or Co2+, Figure 13.1) catalyzed the selective hydroxylation of adamantane with Oz as an oxidant[58,59] ... 

Kinetics of the dimethyidioxirane oxidation of adamantane in an oxygen atmosphere support a radicai mechanism. The kinetics of the oxidation of 2-methyibutane by DMDO in acetone soiution have been studied and the mechanisms of the reaction and of inhibition of the reaction by O2 were discussed. 

The one-electron oxidation of iV-benzylphenothiazine by nitric acid occurs in the presence of /i-cyclodextrin, which stabilizes the radical cation by incorporation into its cavity. The reaction is inhibited by adamantane, which preferentially occupies the cavity. Novel Pummerer-type rearrangements of / -sulfinylphenyl derivatives, yielding /7-quinones and protected dihydroquinones, and highly enantioselective Pummerer-type rearrangements of chiral, non-racemic sulfoxides have been reviewed. A comprehensive study has demonstrated that the redox potential for 7- and 8-substituted flavins is linearly correlated with Hammett a values. DFT calculations in [3.3.n]pro-pellanes highlight low ionization potentials that favour SET oxidative cleavage of the strained central C-C bond rather than direct C-H or C-C bond attack. Oxidations and reductions in water have been reviewed. ... 

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