Oxidation of phenols to hydroxycyclohexadienones using diphenylseleninic anhydride

Barton, Derek H. R.; Magnus, Philip; Rosenfeld, Moshe N.

doi:10.1039/c39750000301

Cited by 23 publications

(14 citation statements)

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“…In search of a solution to futher improve the dimerization yield, it appeared that a reagent capable of delivering an oxygen atom after being fixed on the phenolic oxygen would be ideal for ortho-selective oxygenation. The diphenylseleninic anhydride-mediated Barton oxidation 41,42 was an obvious method to try, but a recent report by Pettus and co-workers 43 on the use of IBX for regioselective ortho-oxygenation of phenols brought us to select this λ 5 -iodane reagent.…”

Section: Methodsmentioning

confidence: 99%

Iodane-mediated and electrochemical oxidative transformations of 2-methoxy- and 2-methylphenols

Quideau¹,

Pouységu²,

Deffieux³

et al. 2003

Arkivoc

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A series of 2-methoxy and 2-methylphenols have been submitted to oxygenative oxidation reactions using (1) the λ 3 -iodane DIB, (2) a non-explosive and non-moisture sensitive version of the λ 5 -iodane IBX, named SIBX for Stabilized IBX, and (3) anodic oxidation with the aim of identifying the best reaction conditions for preparing orthoquinonoid cyclohexadienone synthons. Both the use of DIB and anodic oxidation appeared equally valuable for making orthoquinone dimethyl ketals, but the λ 3 -and λ 5-iodane reagents are more appropriate to induce ortho-oxygenation of 2-methylphenols. In particular, SIBX emerged as a useful reagent for mediating ortho-hydroxylation into dimerizing orthoquinols, a tactic that can be applied to the synthesis of natural bis(monoterpenoids) such as aquaticol.

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Section: Methodsmentioning

confidence: 99%

Iodane-mediated and electrochemical oxidative transformations of 2-methoxy- and 2-methylphenols

Quideau¹,

Pouységu²,

Deffieux³

et al. 2003

Arkivoc

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“…For the generation of ortho-quinols by selec- tive ortho-hydroxylation of 2-substituted arenols such as 47a-c, one should not forget the selenium-based Barton oxidation, in which oxygenation at the ortho position is ensured by intramolecular delivery from the diphenylseleninic anhydride following reaction of the latter with the phenolate anion ( Figure 15) [81,82]. Acid hydrolysis furnished ortho-quinols that spontaneously dimerized to give bicyclo[2.2.2]octenones 48a-c. Pyrolysis of such dimers can be used to regenerate the ortho-quinol parents in situ [180].…”

Section: Metal-based Oxidative Activationmentioning

confidence: 99%

Oxidative Conversion of Arenols into ortho ‐Quinols and ortho ‐Quinone Monoketals – A Useful Tactic in Organic Synthesis

Quideau

2002

Modern Arene Chemistry

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The oxidative activation of arenes is a powerful and versatile synthetic tactic that enables dearomatization to give useful synthons. Central to this chemistry are hydroxylated arenes or arenols, the phenolic functions of which can be exploited to facilitate the dearomatizing process by two-electron oxidation. Suitably substituted arenols can hence be converted, with the help of oxygen-or carbon-based nucleophiles, into ortho-quinone monoketals and ortho-quinols. These 6-oxocyclohexa-2,4-dienones are ideally functionalized for the construction of many complex and polyoxygenated natural product architectures. Today, the inherent and multiple reactivity of arenol-derived ortho-quinone monoketals and orthoquinols species is finding numerous and, in many cases, biomimetic applications in modern organic synthesis. 15.1

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“…In this field and in continuation of our efforts to expand the scope of privileged organocatalysts in the field of selenium chemistry, [6,7] we herein report the first highly enantioselective synthesis of spirolactones starting from racemic cyclic bketoesters and the vinyl selenone catalyzed by bifunctional cinchona-alkaloid-derived catalysts. [12] The presence of the tert-butyl residue seems to be crucial for the cyclization. Particularly indicativeare the 13 C peak at d = 56 ppm, characteristic of a methylene linked to a selenonyl group, [6b, 8] and the 77 Se signal at d = 994 ppm typical of a phenyl alkyl selenone.…”

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confidence: 99%

“…[9] This signal is deshielded in comparison with that of the starting conjugated selenone 2, for which a signal is seen at d = 961 ppm. [12] The presence of the tert-butyl residue seems to be crucial for the cyclization. The excellent leaving ability of the selenone group in intramolecular nucleophilic substitutions is well known, [6,10] thus, plausibly this unprecedented ring-closure reaction occurs through nucleophilic displacement of -SeO 2 Ph by the ester group.…”

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confidence: 99%

“…The excellent leaving ability of the selenone group in intramolecular nucleophilic substitutions is well known, [6,10] thus, plausibly this unprecedented ring-closure reaction occurs through nucleophilic displacement of -SeO 2 Ph by the ester group. [12] The presence of the tert-butyl residue seems to be crucial for the cyclization. [12] The presence of the tert-butyl residue seems to be crucial for the cyclization.…”

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confidence: 99%

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A Highly Enantioselective One‐Pot Synthesis of Spirolactones by an Organocatalyzed Michael Addition/Cyclization Sequence

et al. 2011

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Spirocyclic compounds are attractive targets in organic synthesis because of their broad distribution in biologically active natural products and pharmaceuticals, [1] as well as their increasing use in a range of important chemical and technological processes, such as asymmetric synthesis and organic optoelectronics.[2] On this basis the development of novel methods for the construction of spirocyclic frameworks is of considerable importance, particularly when these methods give rise to the enantioselective formation of an all-carbon quaternary stereocenter, which itself is considered to be a challenging transformation. [3,4] Over the past decade, extensive work on organocatalyzed asymmetric conjugated additions of trisubstituted carbon nucleophiles to electron-deficient alkenes demonstrated that these reactions represent an attractive solution to the problem of selectively generating quaternary stereocenters.[4] Recently several organocatalytic cascade processes involving Michael additions have been successfully applied to the synthesis of spirocyclic compounds.[5] These methods, are based on Michael or Michael/ aldol-type sequences and provide access to spiro-oxindoles, spirobenzofuranones, or spiro-3,4-dihydropyrans with high stereocontrol. The use of novel substrate combinations and the development of new cascade or one-pot reactions are significant advances in this field, thus making the asymmetric assembly of structurally diverse spirocyclic compounds possible from simple and readily available precursors. In this field and in continuation of our efforts to expand the scope of privileged organocatalysts in the field of selenium chemistry, [6,7] we herein report the first highly enantioselective synthesis of spirolactones starting from racemic cyclic bketoesters and the vinyl selenone catalyzed by bifunctional cinchona-alkaloid-derived catalysts. The operationally simple, one-pot Michael addition/cyclization sequence is based on the peculiar properties of the phenylselenonyl substituent, which plays a dual role as an electron-withdrawing group, during the addition step, and as a leaving group, during the cyclization by intramolecular nucleophilic substitution.Initial studies were performed with an excess of the tertbutyl b-ketoester 1 a and the easily available vinyl selenone 2 in toluene in the presence of a catalytic amount of anhydrous Na 2 CO 3 (Scheme 1). The formation of the Michael intermediate 3 a was clearly demonstrated by1 H, 13 C, and 77 Se NMR spectra of the crude reaction mixture. Particularly indicativeare the 13 C peak at d = 56 ppm, characteristic of a methylene linked to a selenonyl group, [6b, 8] and the 77 Se signal at d = 994 ppm typical of a phenyl alkyl selenone.[9] This signal is deshielded in comparison with that of the starting conjugated selenone 2, for which a signal is seen at d = 961 ppm. We were delighted to observe that the Michael adduct was smoothly converted in 2 hours into the spirolactone 4 a by stirring at room temperature with silica gel. The excellent leaving ability ...

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Oxidation of phenols to hydroxycyclohexadienones using diphenylseleninic anhydride

Abstract: Diphenylseleninic anhydride (1) reacts with phenols under neutral conditions to give 0-and phydroxylation, whereas with phenolate anions only o-hydroxylation is observed.

Cited by 23 publications

References 0 publications

Iodane-mediated and electrochemical oxidative transformations of 2-methoxy- and 2-methylphenols

Iodane-mediated and electrochemical oxidative transformations of 2-methoxy- and 2-methylphenols

Oxidative Conversion of Arenols into ortho ‐Quinols and ortho ‐Quinone Monoketals – A Useful Tactic in Organic Synthesis

A Highly Enantioselective One‐Pot Synthesis of Spirolactones by an Organocatalyzed Michael Addition/Cyclization Sequence

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