Studies towards the synthesis of polyoxygenated steroids. Reaction of 7,9(11)-diene steroids with RuO4.

Notaro, Giacomo; Piccialli, Vincenzo; Sica, Donato; Smaldone, D.

doi:10.1016/s0040-4020(01)85020-1

Cited by 31 publications

(17 citation statements)

References 34 publications

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“…Compounds 16, 17, and 18 were identified by comparison with authentic materials. Specifically, compound 18 has spectral properties identical to those of a compound previously obtained by ruthenium tetraoxide oxidation of diene 13, [20] and compounds 16 and 17 have recently been synthesized in our laboratory. [27] However, the complete 1 H and 13 C NMR assignment of keto steroid 16 was now performed with the aid of 1 H-1 H COSY, DEPT, and HMBC experiments (see Supporting Information).…”

Section: Resultsmentioning

confidence: 96%

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Reactivity of Steroidal Dienes towards the Methyltrioxorhenium/H2O2−Urea Oxidation System: Isolation and Characterization of New Oxygenated Steroids

et al. 2001

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To examine the reactivity of conjugated diene steroids towards methyltrioxorhenium (MTO)-catalysed oxidation with the urea−hydrogen peroxide adduct (UHP) and its possible use in functionalization of the rings of the steroid nucleus, the reactions of the MTO/UHP system with cholesta-3,5-diene (4) and 5α-cholesta-7,9(11)-dien-3β-yl acetate (13) in aprotic solvents were investigated. These oxidations were performed both at 0°C and at 25°C, in either CHCl 3 or diethyl ether as solvents, and in the presence of pyridine as ligand.

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Section: Resultsmentioning

confidence: 96%

“…After standing for several hours in CDCl 3 , compound 19 had undergone elimination of H 2 O to give 9α,11α-dihydroxy-5α-cholesta-7,14-dien-3β-yl acetate (20,Figure 2).…”

Section: -Oxo-5α-cholest-9(11)-en-3β-yl Acetate (16)mentioning

confidence: 99%

Reactivity of Steroidal Dienes towards the Methyltrioxorhenium/H2O2−Urea Oxidation System: Isolation and Characterization of New Oxygenated Steroids

et al. 2001

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“…1,2 Though the most popular process mediated by PCC is the oxidation of primary and secondary alcohols to aldehyde and ketones, respectively, many other functional groups undergo PCC oxidation. As a continuation of our interest in oxidative processes mediated by transition metal oxo-species [3][4][5][6][7][8][9][10][11] as well as in the synthesis and derivatization of new THF-containing compounds, [12][13][14][15][16][17][18][19][20][21] we recently focused on oxidation processes mediated by PCC. These studies led to the discovery of new interesting transformations including oxidative spiroketalization, 22 oxidative cleavage of trisubstituted mono-THF compounds 23 and synthesis of bis--acyloxy-1,4-and 1,5-diketones from THF and THP-diols, respectively.…”

Section: Introductionmentioning

confidence: 99%

Pyridinium chlorochromate chemistry. New insight into oxidation of tetrahydrofurans

Zaccaria¹,

Borbone²,

Oliviero³

et al. 2017

Arkivoc

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A thorough investigation of the minor oxidation products of two penta-tetrahydrofuran compounds with pyridinium chlorochromate has been carried out. Isolation of ring-B oxygenated spiroketal and degradation products, including polycyclic mono-and bis-lactone compounds, supports the previously postulated involvement of cyclic enolether intermediates in the oxidation of THF and poly-THF substances with PCC. Based on the collected evidence, a new mechanistic route for the PCC-mediated oxidative cleavage of -hydroxy-THF compounds to -lactones has been postulated. The proposed mechanism well agrees with the one reported for the oxidative cleavage of 8-hydroxy-neoisocedranol oxide by RuO4, a fact that further supports our previous observation on the similar oxidizing behaviour shown by PPC and RuO4 towards THFcontaining compounds.

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“…Previously, we have reported that oxidation of a number of monoene steroids, [16] conjugated diene steroids, [17] and alkenes [18] with RuO 4 leads almost exclusively to 1,2-diols and/or α-hydroxy ketones. Interestingly, some steroidal 1,3-dienes having double bonds located in a hindered position furnished mainly epoxy diols and epoxy ketols upon treatment with RuO 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Interestingly, some steroidal 1,3-dienes having double bonds located in a hindered position furnished mainly epoxy diols and epoxy ketols upon treatment with RuO 4 . [17,19] Furthermore, we have recently demonstrated that these reactions proceed through ruthenium(VI) diesters. [20Ϫ22] In order to explore the generality of the reaction of 1,5-dienes with RuO 4 , to find the optimal reaction conditions, and to shed light on the mechanism of the reaction, we have subjected some 1,5-dienes to RuO 4 -catalysed cyclization.…”

Section: Introductionmentioning

confidence: 99%

Reactions of 1,5-Dienes with Ruthenium Tetraoxide: Stereoselective Synthesis of Tetrahydrofurandiols

2001

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An improved procedure for the ruthenium tetraoxide catalysed oxidation of 1,5-dienes, employing 0.05 equiv. of the catalyst RuO 2 ·2H 2 O, 2.5 equiv. of NaIO 4 as a stoichiometric oxidant, and a biphasic solvent system of AcOEt/(CH 3 ) 2 CO/ H 2 O (2:1:1, v/v/v), is presented. Reactions of 1,5-dienes 1, 3, and 5 furnished the new cis-tetrahydrofuran products 2, 4, 6, and 7 with total stereospecificity. The structures of the products have been established on the basis of NMR and MS data, as well as chemical evidence. Application of this procedure to geranyl acetate (8) and neryl acetate (12) afforded the cis-tetrahydrofuran derivatives 9, 10, and 13 in high yields, accompanied by small amounts of trans-tetrahydrofu-

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Studies towards the synthesis of polyoxygenated steroids. Reaction of 7,9(11)-diene steroids with RuO4.

Cited by 31 publications

References 34 publications

Reactivity of Steroidal Dienes towards the Methyltrioxorhenium/H2O2−Urea Oxidation System: Isolation and Characterization of New Oxygenated Steroids

Reactivity of Steroidal Dienes towards the Methyltrioxorhenium/H2O2−Urea Oxidation System: Isolation and Characterization of New Oxygenated Steroids

Pyridinium chlorochromate chemistry. New insight into oxidation of tetrahydrofurans

Reactions of 1,5-Dienes with Ruthenium Tetraoxide: Stereoselective Synthesis of Tetrahydrofurandiols

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