Remote oxidation of ketones to ?- and ?-diketones

Troyanskii, E. I.; Mizintsev, V. V.; Lazareva, M. I.; Demchuk, D. V.; Nikishin, G. I.

doi:10.1007/bf00957783

Cited by 2 publications

(2 citation statements)

References 13 publications

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“…14, 15 Presumably, in the first step of the oxidation of cyclo hexanone as an example, an O centered radical cation is formed, one of its reaction routes involves 1,5 shift of a hydrogen atom to generate C centered radical cation, which is oxidized to cyclohexane 1,4 dione (the yield is ∼2%). But if this were the case, the simultaneous 1,3 and 1,4 migration of a hydrogen atom would occur.…”

Section: Methodsmentioning

confidence: 99%

Electrosynthesis of glutaric acid and regularities of electrocatalytic oxidation of cycloalkanones at a NiOOH anode in aqueous NaOH

Lyalin

Petrosyan

2009

Russ Chem Bull

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Methods of preparation of glutaric acid by oxidation of cyclopentanone or pentane 1,5 diol in an undivided cell at a NiOOH electrode in aqueous alkali are developed. Yields of the products were 51% or 90%, respectively. The mechanism of electrooxidation of cycloalkan ones at a NiOOH electrode is discussed on the basis of literature data and the regularities of the oxidative transformations of cyclohexanone investigated earlier and those of cyclo pentanone.We have been investigating the electrosynthesis in aqueous alkaline media using a Ni anode and the un divided cell for several years. 1-3 On the surface of a Ni anode, NiOOH is formed during electrolysis under these conditions. This is an efficient oxidant, which is self generated in the electrolysis. In particular, this approach was used for the development of two methods for the preparation of adipic acid 1 : by direct oxidation of cyclo hexanol (the yield was 47%) and by the oxidation of cyclohexanol to cyclohexanone (the yield was 75%) fol lowed by oxidation of the latter to adipic acid (the yield was 52%). The same approach was used in the present work for the preparation of glutaric acid, which is used in the synthesis of herbicides 4 and pharmaceuticals. 5 It is of note that cyclopentanol is not promising as the starting material because it is prepared by hydrogenation of cyclopentanone, which is more accessible. 6,7 Therefore, it was cyclopentanone that we chose as an initial subject of investigations. Besides, the oxidation of an available acyclic 1,5 diol was studied as an alternative for the syn thesis of glutaric acid. The results of the investigations were used for generalization of the existing literature data on the regularities of the electrooxidation of cyclo alkanones. Results and DiscussionThe first experiments on the electrooxidation (EO) of cyclopentanone (CP) at a NiOOH anode in aqueous NaOH (Table 1, entry 1) resulted in the formation of glutaric acid in the yield of ~44% (based on the consumed ketone). The oxidation process is presented in Scheme 1, it is similar to the scheme of EO of cyclohexanone under the same conditions. 1 Scheme 1In the studies of EO of CP it was found that a decrease in the temperature of electrolysis from 25 to 10°C led to the increase in the yield of glutaric acid by 13% (cf. entries 1 and 2, Table 1). With increased concentration of alkali from 0.8 to 1.0 mol L -1 , the yield of the acid also increased, however it decreased again at higher (1.2 mol L -1 ) concentration of the alkali (cf. entries 2, 3, and 4, Table 1).The increase in the concentration of CP from 0.1 to 0.2 mol L -1 is favorable for the increase in the yield of glutaric acid (by 20% based on loaded CP) and the con version of CP (by 35%) (cf. entries 2, 5, and 6, Table 1). The dependence of the yield of glutaric acid on current density passes through a maximum (cf. entries 2, 7, and 8, Table 1) reaching 58% (based on consumed cyclopentan one) at J = 6 mA cm -2 . Thus, the conditions were found (Т = 10°C, С CP = 0.15-0.2 mol L -1 , С NaOH = 1.0 mol ...

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Section: Methodsmentioning

confidence: 99%

Electrosynthesis of glutaric acid and regularities of electrocatalytic oxidation of cycloalkanones at a NiOOH anode in aqueous NaOH

Lyalin

Petrosyan

2009

Russ Chem Bull

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“…The regioselectivity observed here (2.4:1) differs significantly from that seen in Na 2 S 2 O 8 oxidation of the same substrate. The Na 2 S 2 O 8 oxidation , gave a ratio of 1.15:1 of 2,6- and 2,5-heptanedione products with Fe II as an additive and a ratio of 1:1.4 without Fe II , where the regioselectivity is the opposite of that with 2 and NaIO 4 . For this reaction an intramolecular free radical mechanism was proposed, which should not occur with our nonradical Cp*Ir/NaIO 4 system, consistent with the different product distribution observed.…”

Section: Resultsmentioning

confidence: 99%

Cp* Iridium Precatalysts for Selective C–H Oxidation with Sodium Periodate As the Terminal Oxidant

et al. 2013

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Sodium periodate (NaIO 4 ) is shown to be a milder and more efficient terminal oxidant for C−H oxidation with Cp*Ir (Cp* = C 5 Me 5 ) precatalysts than ceric(IV) ammonium nitrate. Synthetically useful yields, regioselectivities, and functional group tolerance were found for methylene oxidation of substrates bearing a phenyl, ketone, ester, or sulfonate group. Oxidation of the natural products (−)-ambroxide and sclareolide proceeded selectively, and retention of configuration was seen in cis-decalin hydroxylation. At 60 °C, even primary C−H bonds can be activated: whereas methane was overoxidized to CO 2 in 39% yield without giving partially oxidized products, ethane was transformed into acetic acid in 25% yield based on total NaIO 4 . 18 O labeling was demonstrated in cis-decalin hydroxylation with 18 OH 2 and NaIO 4 . A kinetic isotope effect of 3.0 ± 0.1 was found in cyclohexane oxidation at 23 °C, suggesting C−H bond cleavage as the rate-limiting step. Competition experiments between C−H and water oxidation show that C−H oxidation of sodium 4-ethylbenzene sulfonate is favored by 4 orders of magnitude. In operando time-resolved dynamic light scattering and kinetic analysis exclude the involvement of metal oxide nanoparticles and support our previously suggested homogeneous pathway.

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Remote oxidation of ketones to ?- and ?-diketones

Cited by 2 publications

References 13 publications

Electrosynthesis of glutaric acid and regularities of electrocatalytic oxidation of cycloalkanones at a NiOOH anode in aqueous NaOH

Electrosynthesis of glutaric acid and regularities of electrocatalytic oxidation of cycloalkanones at a NiOOH anode in aqueous NaOH

Cp* Iridium Precatalysts for Selective C–H Oxidation with Sodium Periodate As the Terminal Oxidant

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