An economical and green approach for the oxidation of olefins to enones

Marwah, Padma; Marwah, Ashok; Lardy, Henry A.

doi:10.1039/b408974j

Cited by 42 publications

(31 citation statements)

References 20 publications

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“…Caution must be taken when comparing the reported yields because there were various methods used to identify "isolated" yields (using HPLC instead of obtaining mass for example) [20], differing standards on purity of the isolated product (i.e., reporting an isolated yield that is 67% pure) [19], differing sampling sizes, and an overall lack of supporting information. Several reported steroidal allylic oxidation reactions have not been included in the tables due to low yields of 7-keto product, such as oxygen irradiation with and without photosensitizer [24] and Gif chemistry [25].…”

Section: Reported Methodsmentioning

confidence: 99%

“…Indeed, tert-butoxide and tert-butyl peroxy radicals are formed through degradation of TBHP by catalysts. Those radicals then oxidize steroidal compounds [19,20,[26][27][28][29][30][31][32][33]36].…”

Section: Reported Methodsmentioning

confidence: 99%

“…Likewise, TBHP degradation by metal leads to radicals that form a C7 peroxide. Bleach initiates radical formation from TBHP, similar to the metal catalysts [20]. When only sodium chlorite and NHPI are used, NHPI becomes phthalimide N-oxyl (PINO), a radical initiator of molecular oxygen [19].…”

Section: Reported Methodsmentioning

confidence: 99%

“…From chromium based catalysts, the next phase in steroidal allylic oxidation manifested through more environmentally friendly metallic catalysts that use TBHP as an oxygen donor. Meanwhile, several methods have been reported to give steroidal oxidation without any metal catalysts using as sodium chlorite and sodium hypochlorite [19,20] supported and organometallic polymer catalysts, have been reported to yield allylic oxidation products of steroidal compounds [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

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A Short Review of Methods for the Allylic Oxidation of Δ5 Steroidal Compounds to Enones

Sg¹,

Jp²

2016

J Steroids Horm Sci

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Introduction of α, β-unsaturated ketones to ∆ 5 steroidal olefins changes the characteristics and biological function of those compounds. Several synthetic methods have been reported to accomplish carbonyl introduction to ∆ 5 steroidal olefins. Herein, this short review will catalogue many of those oxidative methods, particularly those proceeding through a peroxide intermediate and/or use chromium complexes as reagents. to undesired side products, one in particular being C25 for steroids with side chains [15]. Furthermore, cleavage of the side chain can occur concurrent with allylic oxidation [16].Protecting the C3 hydroxy group is commonly accomplish by esterification using acetic anhydride to make cholesteryl acetate. The authors of this review prefer esterification with benzoyl chloride since cholesteryl benzoate products can be more easily isolated with recrystallization in acetone and water than the steroidal acetates. This esterification is necessary because many oxidants and catalysts will convert the C3 hydroxyl group to a ketone [17].Due to interest in "green" or environmentally benign chemistry, chemists have questioned the ethics of earlier catalysts. Environmental and health concerns have motivated the search for new oxidants and catalysts [18]. From chromium based catalysts, the next phase in steroidal allylic oxidation manifested through more environmentally friendly metallic catalysts that use TBHP as an oxygen donor. Meanwhile, several methods have been reported to give steroidal oxidation without any metal catalysts using as sodium chlorite and sodium hypochlorite [19,20]. Additionally, recoverable heterogeneous catalysts, clay

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Section: Reported Methodsmentioning

confidence: 99%

Section: Reported Methodsmentioning

confidence: 99%

Section: Reported Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Short Review of Methods for the Allylic Oxidation of Δ5 Steroidal Compounds to Enones

Sg¹,

Jp²

2016

J Steroids Horm Sci

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“…Jurado-Gonzalez et al 13 reported similar results using tert-butyl hydroperoxide and catalytic amounts of cobalt (II) alkyl phosphonate modified silica. Recently, Marwah et al reported 14 an economical and green approach for the oxidation of olefins to enones, using household laundry bleach and aqueous tert-butyl hydroperoxide, but with lower isolated technical product yields.…”

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confidence: 99%

Bismuth-catalyzed allylic oxidation using t-butyl hydroperoxide

Salvador

Silvestre

2005

Tetrahedron Letters

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Allylic Oxidation Catalyzed by Dirhodium(II) Tetrakis[ε‐caprolactamate] oftert‐Butyldimethylsilyl‐protectedtrans‐Dehydroandrosterone

et al. 2014

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e‐Caprolactam Dirhodium(Ii) tetrakis[e‐caprolactamate] tert ‐Butylhydroperoxide 1,2‐Dichlorethane TBDMSCl 1 H ‐Imidazole N,N ‐Dimethylformamide Androst‐5‐en‐17‐one Androst‐5‐ene‐7,17‐dione

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An economical and green approach for the oxidation of olefins to enones

Cited by 42 publications

References 20 publications

A Short Review of Methods for the Allylic Oxidation of Δ5 Steroidal Compounds to Enones

A Short Review of Methods for the Allylic Oxidation of Δ5 Steroidal Compounds to Enones

Bismuth-catalyzed allylic oxidation using t-butyl hydroperoxide

Allylic Oxidation Catalyzed by Dirhodium(II) Tetrakis[ε‐caprolactamate] oftert‐Butyldimethylsilyl‐protectedtrans‐Dehydroandrosterone

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