Asymmetric epoxidation of unfunctionalized alkenes by dioxirane intermediates generated from potassium peroxomonosulphate and chiral ketones

Curci, Ruggero; Fiorentino, Michele; Serio, Maria R.

doi:10.1039/c39840000155

Cited by 159 publications

(72 citation statements)

References 5 publications

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“…Dioxiranes have been shown to be one of the most versatile reagents for epoxidation as they transfer an oxygen atom efficiently to a variety of organic substrates (Curci et al, 1984). The preparation can be either in an isolated solution or in-situ (Scheme 5) (Frohn et al, 1998).…”

Section: Dioxiranesmentioning

confidence: 99%

Modification of olefinic double bonds of unsaturated fatty acids and other vegetable oil derivatives via epoxidation: A review

et al. 2017

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SUMMARY:The highly strained ring in epoxides makes these compounds very versatile intermediates. Epoxidized vegetable oils are gaining a lot of attention as renewable and environmentally friendly feedstock with various industrial applications such as plasticizers, lubricant base oils, surfactants, etc. Numerous papers have been published on the development of the epoxidation methods and the number is still growing. This review reports the synthetic approaches and applications of epoxidized vegetable oils. KEYWORDS: Epoxidation; Renewable feedstock; Unsaturated fatty acids; Vegetable Oils RESUMEN:Modificación del doble enlace olefínico en ácidos grasos insaturados y en derivados de aceites vegetales via epoxidación: Revisión. La alta tensión del anillo en los epóxidos hace que estos compuestos intermediarios sean muy versátiles. Los aceites vegetales epoxidados están ganando mucha atención como materia prima renovable y respetuosa con el medio ambiente con diversas aplicaciones industriales, tales como plastificantes, aceites base para lubricantes, tensioactivos, etc. Por esta razón, se han publicado numerosos trabajos sobre el desarrollo de métodos de epoxidación y el número todavía es creciente. Esta revisión aporta información sobre enfoques sintéticos y aplicaciones de aceites vegetales epoxidados.

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Section: Dioxiranesmentioning

confidence: 99%

Modification of olefinic double bonds of unsaturated fatty acids and other vegetable oil derivatives via epoxidation: A review

et al. 2017

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“…Treatment of 1-methylcyclohexene and trans-2-methylstyrene with chiral ketones 52 and 53 (Figure 35.6) and Oxone in CH 2 Cl 2 -H 2 O in the presence of Bu 4 NHSO 4 provided the corresponding epoxides in 60-92% yield and 9-12.5% enantomeric excess. 38 In 1996, Yang and co-workers reported on a C 2 -symmetric chiral binaphthyl ketone 54 as an efficient catalyst for the asymmetric epoxidation of unfunctionalized olefins. 39 In ketone 54, a remote binaphthalene unit was used as the chiral control element to make the catalytic center less hindered, and the electron-withdrawing esters at the a-carbon made ketone 54 very reactive (Figure 35.7).…”

Section: Dioxirane-catalyzed Epoxidationsmentioning

confidence: 99%

Asymmetric Epoxidation in Stereoselective Synthesis

Yang

2013

Stereoselective Synthesis of Drugs and Natural Products

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Asymmetric epoxidation of olefins has been proven to be one of the most important methods to generate chiral epoxides, which are highly useful intermediates in the stereoselective synthesis of biologically interesting compounds. In this chapter, several powerful and practical asymmetric epoxidation methods and their utilities for the stereoselective synthesis of drug substances and natural products are described. The representative asymmetric epoxidation methods that are described in the chapter include directed epoxidations, metal oxo‐catalyzed epoxidations, dioxirane‐catalyzed epoxidations, nucleophilic epoxidations, and asymmetric phase‐transfer–catalyzed epoxidations.

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“…The examples described above do not include the enantioselective syntheses of 2-substituted dihydroquinolines, but it is worth noting that excellent enantioselectivities have been reported independently by Shibasaki (96 % ee) 42 , Takemoto (97% ee) 43 and Alexakis (75% ee) respectively. 44 The work reported in this chapter looks to employ an enantioselective iminium-salt catalysed epoxidation step to form enantioenriched tetrahydroquinoline products from various prochiral dihydroquinoline substrates.…”

Section: Tandem Michael-aldol Additionsmentioning

confidence: 99%

Recent Advances in Iminium‐Salt‐Catalysed Asymmetric Epoxidation

Day

Sellars

2016

Eur J Org Chem

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The research in this thesis depicts some of the most current developments in the area of asymmetric epoxidation of alkenes using chiral iminium salt catalysts. The first chapter reviews past and present developments in; catalytic asymmetric epoxidation, and covers the application of this reaction towards the kinetic resolution of racemic olefins.Chapter two is separated into two key areas; (i) asymmetric epoxidation as a tool in the kinetic resolution of racemic chromene substrates, and (ii) investigations into the asymmetric epoxidation of new N-protected dihydroquinoline substrates. In the first part of chapter two, the first examples of kinetic resolution in epoxidation reactions using iminium salt catalysts are reported, providing up to 98% ee in the epoxidation of racemic cis-chromenes.The second part of chapter two details the first known examples of asymmetric epoxidation upon nitrogen-protected dihydroquinoline substrates, affording enantioselectivities as high as 73% ee.In both parts of chapter two, non-aqueous epoxidation conditions were employed using Page's dihydroisoquinolinium iminium salt catalyst. The later part of chapter two introduces a biphenylazepinium iminium salt catalyst used under aqueous epoxidation conditions. Chapter three includes experimental data for all the compounds mentioned in chapter two, with chapter four containing HPLC traces to show determination of enantiomeric excess of epoxides, and enantioenriched alkene traces.iii ACKNOWLEDGEMENTS

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Asymmetric epoxidation of unfunctionalized alkenes by dioxirane intermediates generated from potassium peroxomonosulphate and chiral ketones

Abstract: Chiral dioxirane intermediates, which are formed in the reaction of potassium peroxomonosulphate with chiral ketones, allow the epoxidation of simple pro-chiral olefins to the corresponding epoxides to be carried out with enantiomeric excesses in the range 9-1 2.5%.

Cited by 159 publications

References 5 publications

Modification of olefinic double bonds of unsaturated fatty acids and other vegetable oil derivatives via epoxidation: A review

Modification of olefinic double bonds of unsaturated fatty acids and other vegetable oil derivatives via epoxidation: A review

Asymmetric Epoxidation in Stereoselective Synthesis

Recent Advances in Iminium‐Salt‐Catalysed Asymmetric Epoxidation

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