Alkanes, cyclo oxides

In yet another version of adopting a biphase system, oxidation of alkanes with rert-butyl hydroperoxide has been conducted with an aqueous phase. Launay et al. (1998) have developed an efficient and highly selective conversion of cyclo-octane to cyclo-octanone using Ru colloidial particles formed in situ from RuCli. 5H2O. The aqueous phase can be recycled. 

K[Ru(0)(PDTA)].3Hj0 and Ru(0)(HEDTA) (PDTA=(propylenediaminetetra-acetate) -) are made by oxidation of K[Ru "Cl(PDTA.H)] or K[Ru" Cl(EDTA.H)] with PhIO electronic and ESR spectra were recorded. Rates and activation energies for epoxidation by stoich. Ru(0)(PDTA)] or Ru(0)(HEDTA)/water-dioxane of cyclo-alkanes were measured, as were those for oxidation of cyclohexane to cyclohexanol and cyclohexanone [632],... 

RuCl2(H20) ]+ This species was made from RUCI3 in HCl from pH 0.4-2.0. Kinetic studies suggest that in the epoxidation by [Ru(7l2(H20)4]X02/water-dioxane of cyclo-octene and -hexene homolytic cleavage of the 0-0 bond plays an essential part [771, 772], and that this is so for similar oxidation of alkanes (e.g. of cyclohexane to cyclohexanol) [771],... 

CIS-[Ru(H20)2(dinso) ] is made from as-RuClj(dmso) and Ag(BF ) in aq. EtOH. The system c/s-[Ru(H20)j(dmso) ] Vaq. Na(ClO) or TBHP/CH Cl oxidised alkanes such as adamantane, cyclo-octane, -heptane and -hexane to the corresponding alcohols and ketones as did [Ru(Hj0) PWjj(0)3g ] . A free-radical mechanism may be involved for the TBHP oxidations, but those with (C10) probably involve oxoruthenate(VI) or oxoruthenate(IV) intermediates [823], The oxidative destruction of a-chlorinated alkenes by CM-[Ru(HjO)2(dmso) ] Vaq. Oxone /Me(CH3) jN(HSO ) MCj to carboxylic acids and ultimately to CO and HCl was reported [946],... 

The Bashkirov oxidation (liquid-phase oxidation of n-alkanes or cycloalkanes in the presence of boric acid and hydrolysis) yields the corresponding secondary alcohols [16, 17]. The reaction is used industrially for oxidation of C10 to C18 n-alkanes, providing raw materials for detergents and for oxidation of cyclododecane to cyclo-dodecanol as an intermediate for the production of Nylon 12 (Table 1, entry 8). The process is not of much commercial importance in the western world, however. Oxidation in the absence of boric acids usually leads to mixtures of alcohols, ketones, and carboxylic acids (Table 1, entry 9). 

Figure 1.15 shows the product profiles for the mixture containing 2.5, 140 and 357.5 Torr of cyclohexane, H2 and O2 at 753 K. The results are typical of the quality of data obtained not only from cyclohexane but alkanes and related compounds in general. Primary and secondary products may be characterized from the shape of the profiles. Cyclohexane, 7-oxabi-cyclo(2,2,l)heptane (1,4 cyclohexane oxide), 1,2 epoxycyclohexane, CH2=CHCH2CH2CH2CH0 (hex-5-en-l-al), buta-1,3-diene and possible... 

The insertion of oxygen into a C-H-bond via allylic oxidation or alkane oxidation is a difficult reaction and not many efficient methods are known in the literature [32]. Recently, a fluorinated manganese catalyst solubilized in a perfluorinated solvent has found application in the oxidation of cyclohexene to cyclo-hexenol and cyclohexenone [33, 34]. As catalyst precursor the manganese salt of... 

The action of hydroxylamine on the dibromo-ketone (327) unexpectedly resulted in the isoxazoline (328)." The spiro-isoxazoline (330) is formed by anodic oxidation of the phenolic oxime (329)." Three novel reactiom leading to isoxazolines have been reported the nitrone PhCH=CHCPh=N-(CH2SMe)-0 undergoes 1,5-dipolar cyclization and elimination on heating, to yield compound (331)," silylation of secondary nitro-alkanes gives silyl-nitronates, which, in the presence of triethylamine, undergo 1,3-cyclo-addition to olefins thus sequential treatment of MejCHNOa with trimethyl-... 

The primary steps in the oxidation of iso- and cyclo-alkanes are probably the same as in the case of -alkanes. However, the number, size and arrangement of side chains at the alkane molecule appear to have a stronger influence on the oxidation capacity. No general rules have yet been worked out, and only a few points are clear ... 

Reports of the kinetics of ceric oxidation of a variety of different alcohols have been made. The substrate molecules include mono-, di- and trihydroxyalkanes, cyclo-alkanols (cychc alkane alcohols) and phenols (table 3). Hydroxyacids have also been investigated and will be discussed in the section on carboxylic acids. Ceric oxidation of carbohydrates is discussed along with aldehydes and ketones. In those studies with excess substrate, the dominant products (where discussed) are the corresponding aldehydes and ketones. The most remarkable aspect of these investigations is that the resolved values for the stability constants of many of the precursor complexes exceed those observed in analogous Ce(lV)-carboxylic acid oxidations. 

Substitution of extra-annular hydrogen atoms of the cyclic mono-ethers seems to have the same effect on the heat of polymerization as it does in the case of the cyclo-alkanes. Thus, for the 3,3-disubstituted-l-oxacyclobutanes the heats of polymerization are less than for the parent compound, trimethyiene oxide. 

Also, the Schreiner group published in 2009 a desymmetrisation approach of meso-(cyclo)alkane-l,2-diols applying the lipophilic peptide catalyst 7 (Scheme 13.8) already successfully used in kinetic resolution processes (Scheme 13.5) as previously described. The desymmetrisation step was combined in one pot with a direct TEMPO oxidation to the corresponding ot-aceto)y ketone in order to avoid racemisation of the monoacelylated intermediate. 

Interestingly, Shul pin applied the same catalytic system to alkanes dissolved in acetonitrile and reported the successful formation of the related all l hydroperoxides. For instance, cyclo-octane hydroperoxide was formed in 31% yield after 32 h at 70 °C. As in the case of Schuchardt, the aluminium species is proposed to play a role in the formation of hydrojgrl radicals actually responsible for the oxidation. ... 

---