Hypervalent iodine oxidation of p-alkoxyphenols and related compounds: a general route to p-benzoquinone monoacetals and spiro lactones

Tamura, Yasumitsu; Yakura, Takayuki; Hoshino, Junichi; Kita, Yasuyuki

doi:10.1021/jo00226a041

Cited by 318 publications

(124 citation statements)

References 1 publication

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“…Thus, oxidation of 22 with PhI(CO 2 CF 3 ) 2 [11] in the presence of PMBOH produced PMB ketal quinone 23, as a single diastereomer, in 87 % yield. Based on steric considerations, the stereochemistry of the PMB ketal 23 was tentatively assigned as having the a configuration as shown in Scheme 6, which was presumed to originate from attack of PMBOH from the bottom face of the cationic intermediate.…”

Section: Methodsmentioning

confidence: 97%

Synthesis of the Sporolide Ring Framework through a Cascade Sequence Involving an Intramolecular [4+2] Cycloaddition Reaction of an o‐Quinone

Nicolaou¹,

Wang²,

Tang³

2008

Angewandte Chemie

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In a recent publication, Fenical and co-workers [1] reported the structural characterization of the two unique molecular frameworks of sporolides A (1) and B (2; Scheme 1). Isolated from the fermentation broths of a strain of the marine-derived actinomycete Salinispora tropica, these compounds feature molecular architectures that contain 24 carbon atoms (among which only two are not oxygenated or sp 2 hybridized), 10 stereogenic centers, and no less than seven rings. These marine natural products present an intriguing synthetic challenge in view of their unprecedented molecular structures and the opportunity they present for the development of novel synthetic strategies. Herein we report the construction of model system 3, which represents the structural skeleton of sporolide A (1) and B (2) and contains all seven rings of the naturally occurring molecules, through a cascade sequence involving an unprecedented intramolecular [4+2] cycloaddition reaction of an olefinic o-quinone.Scheme 2 shows the retrosynthetic analysis of the sporolide model system 3. Thus, the target molecule was envisioned to arise by selective manipulation of the trioxygenated aromatic nucleus of hexacyclic compound 4 a, whose macrocycle and dioxane moieties were simultaneously dismantled through a retro o-quinone [4+2] cycloaddition reaction to reveal o-quinone ester 5 as a possible intermediate, whose generation from catechol 6 was considered standard. While the origin of precursor 6 was clear (that is, from building blocks 7 and 8), the transformation of o-quinone 5 to macrocycle 4 a through the intended cycloaddition reaction was based on a rather daring hypothesis since we were aware of no precedent for such an intramolecular reaction of an o-quinone. [2,3] Furthermore, should such a scenario be possible, its stereochemical outcome could only be speculated upon at the outset. Encouragingly, both molecular models and molecular mechanics calculations, together with electronic considerations, indicated the desired regio-and diatereoisomer to be favored. Thus, of the four possible isomers of 4 a (4 a-4 d, Scheme 3), the desired isomer 4 a was predicted to be the most favored on the basis of electronic (preferential activation of the C6-carbonyl oxygen atom by the C4'-OBn moiety; conjugated addition of the C6-carbonyl oxygen atom onto C10 of the olefinic bond, Scheme 1. Molecular structures of sporolides A (1) and B (2) as well as sporolide ring framework 3.Scheme 2. Retrosynthetic analysis of sporolide ring framework 3.

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Section: Methodsmentioning

confidence: 97%

Synthesis of the Sporolide Ring Framework through a Cascade Sequence Involving an Intramolecular [4+2] Cycloaddition Reaction of an o‐Quinone

Nicolaou¹,

Wang²,

Tang³

2008

Angewandte Chemie

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“…A reagent combination of PhI(OAc) 2 and PhI(OCOCF 3 ) 2 converted 8 into the naphthoquinone monoketal 9 in a mixture of CH 3 CN and ethylene glycol. 15 The acetyl group of 9 was then removed by saponication to produce 10. When 10 was treated with 2 propenyl tri uoroborate in the presence of catalytic Rh(cod) 2 BF 4 (10 mol%), (S) BINAP (15 mol%), and stoichiometric Et 3 N, 16,17 the asymmetric 1,4 addition proceeded smoothly, providing 7 in 91% yield and 90% ee.…”

Section: Synthesis Of the Ab Ring Structurementioning

confidence: 99%

Asymmetric Total Synthesis of (−)-4-Hydroxyzinowol, a Highly Oxygenated Dihydro-β-Agarofuran

Urabe¹,

Todoroki²,

Inoue

2015

J. Synth. Org. Chem. Jpn.

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“…[112][113][114][115][116][117][118] Many attempts to make spirodienones in vitro have been achieved by oxidative phenolic coupling reaction using heavy metal oxidizing reagents such as vanadium(V), iron(III), manganese(IV), or thallium(III) salts, but unsatisfactory results were encountered in many cases. [119][120][121][122][123][124][125][126][127][128][129][130][131] Alternatively, phenolic coupling reactions using hypervalent iodine(III) reagents could also lead to spirodienones from para-substituted phenols 79,82,[132][133][134][135][136] ; however, phenolic instability often causes difficulties in smooth conversions. Therefore the development of effective routes to spirodienones remains an important topic in organic synthesis.…”

Section: Oxidative Non-phenolic Coupling Reaction Leading To Biarylsmentioning

confidence: 99%

“…[157][158][159][160] Generally, these are synthesized by oxidative (biomimetic) phenolic coupling reaction; a large number of reagents for this purpose have been developed. [161][162][163][164] In contrast to the oxidation of phenol derivatives, the use of phenyl ethers for oxidative aromatic nucleophilic substitution reaction could be efficient alternatives to afford spirodienone lactones and spirodienone ethers; however, early investigations using heavy metal reagents reported low yields. 165) To investigate the utility of PhI(OCOCF 3 ) 2 -HPA in the intramolecular oxidative cyclization reaction of phenyl ethers to oxygen heterocycles, oxidation of 3-(3,4-dimethoxyphenyl)-propionic acid (8a) using various oxidation systems was examined (Table 11).…”

Section: Synthesis Of Spirodienone Ethers and Spirodienone Lactonesmentioning

confidence: 99%

Development and Application of New Oxidation Systems Utilizing Oxometalate Catalysts

Hamamoto

2012

CHEMICAL & PHARMACEUTICAL BULLETIN

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This review describes our recent efforts in the development and application of new oxidation systems utilizing oxometalate catalysts. The novel use of heteropoly acid (HPA), an acidic oxometalate catalyst, in hypervalent iodine-mediated oxidations provided an effective strategy to generate cation radical species that enables a variety of direct C-H functionalizations of aromatic compounds. This strategy brought a facile biaryl synthesis and new spirodienone syntheses in aromatic oxidation chemistry. Moreover, this strategy opens up a facile synthetic route to morphinandienone alkaloids. On the other hand, the use of oxometalate catalyst together with poly(N-isopropylacrylamide) (PNIPAAm)-based polymer in the development of new solid-phase catalyst provided a novel reaction system in water. Due to the characteristic temperature-responsive intelligence of PNIPAAm, this reaction system brought a remarkable acceleration of the reactivity and ease of catalyst recovering in catalytic oxidation that uses hydrogen peroxide or oxygen gas (O 2 ) as primary oxidant. In addition, the recovered solid-phase catalyst could be used for consecutive reactions without any significant loss of its catalytic efficacy.

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Hypervalent iodine oxidation of p-alkoxyphenols and related compounds: a general route to p-benzoquinone monoacetals and spiro lactones

Cited by 318 publications

References 1 publication

Synthesis of the Sporolide Ring Framework through a Cascade Sequence Involving an Intramolecular [4+2] Cycloaddition Reaction of an o‐Quinone

Synthesis of the Sporolide Ring Framework through a Cascade Sequence Involving an Intramolecular [4+2] Cycloaddition Reaction of an o‐Quinone

Asymmetric Total Synthesis of (−)-4-Hydroxyzinowol, a Highly Oxygenated Dihydro-β-Agarofuran

Development and Application of New Oxidation Systems Utilizing Oxometalate Catalysts

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