Efficient oxidative dimerization of 1-naphthols to 2,2′-binaphthyls with dioxygen mediated by semiconductors

Otsuka, Tsuyoshi; Okamoto, Iwao; Kotani, Eiichi; Takeya, Tetsuya

doi:10.1016/j.tetlet.2004.01.133

Cited by 17 publications

(13 citation statements)

References 25 publications

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“…Most mechanisms proposed in the literature for both oxide‐mediated and uncatalyzed oxidative coupling reactions of 2‐ and 4‐substituted naphthols involve radicals 2. 3, 12, 13 The reaction sequence proposed (Scheme ) for the metal catalyzed reaction of 1 is related to this group of mechanisms, but the “radical” is stabilized by bonding to the metal surface (e.g. Pt).…”

Section: Resultsmentioning

confidence: 99%

“…2 The oxidative coupling of naphthol compounds is an important reaction principle that can be used for this purpose. With hydroxyarene derivatives, such as phenols and naphthols, the reaction usually involves an oxidative dehydrogenation step and the subsequent CC or CO coupling of the resulting arenyl radicals 3. This reaction pattern is also used in hair dyeing.…”

Section: Introductionmentioning

confidence: 99%

“…Examples are Cr IV , Mn III , Fe III , Cu II , Ag I , and Pb IV compounds 1. 3 The use of stoichiometric reagents often leads to poor coupling selectivity, low yield, and the formation of by‐products 3. Another problem is the disposal of the reduced (toxic) oxidants and of the undesired side products 9.…”

Section: Introductionmentioning

confidence: 99%

“…For the sake of sustainable chemistry, these stoichiometric reactions should be replaced with environmentally friendly catalytic methods 2. 3…”

Section: Introductionmentioning

confidence: 99%

“…found that 4‐methoxy‐1‐naphthol ( 5 ) couples in the presence of oxygen and semiconductors, such as SnO 2 and ZrO 2 , to give binaphthols and binaphthoquinones, which are of importance for the pharmaceutical industry (Scheme ) 2. 3 These compounds are also useful intermediates for the preparation of naturally occurring substances, such as diosindigo B, biramentaceone, and violet‐quinone 2…”

Section: Introductionmentioning

confidence: 99%

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Oxidative Coupling of 1‐Naphthols over Noble and Base Metal Catalysts

2013

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Bismuth‐promoted platinum catalysts were tested for the oxidative coupling of 2‐ and 4‐substituted 1‐naphthols at different temperatures and ambient pressure. The principal final products are the 3,3′‐substituted 1,1′‐binaphthalenylidene‐4,4′‐diones and the 4,4′‐substituted 2,2′‐binaphthalenylidene‐1,1′‐diones, respectively. Hydrogen peroxide was used as the oxidant. Only naphthols with electron‐donating substituents reacted. The corresponding binaphthalenyl diols can be considered as reaction intermediates. Yields of up to 99 % were obtained from 2‐methyl‐1‐naphthol as the starting material within 20 minutes. Probably for steric reasons, the diol is the final product obtained from 2‐ethyl‐1‐naphthol. For 4‐methoxy‐1‐naphthol the outcome is determined by the reaction temperature. At 25 °C the expected 1,1′‐dione is the major product, whereas at 60 °C 1′‐hydroxy‐4′‐methoxy‐2,2′‐binaphthalenyl‐1,4‐dione is formed; the loss of one methoxy unit and the preservation of the hydroxy group can be explained by the competitive cleavage of one of the two OMe bonds at higher temperature. Unpromoted platinum and a range of other metallic catalysts, including gold and Raney nickel, were also found to be active. The products obtained are brightly colored solids that could be used as dyes. The method described is truly catalytic and environmentally benign. The potential of the technique justifies further research to expand on the applicability of this novel method.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…For the sake of sustainable chemistry, these stoichiometric reactions should be replaced with environmentally friendly catalytic methods 2. 3…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Oxidative Coupling of 1‐Naphthols over Noble and Base Metal Catalysts

2013

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Rhodaelektro‐katalysierte peri‐selektive direkte Alkenylierungen mit schwacher O‐Koordination ermöglicht durch die Wasserstoffbildungsreaktion (HER)

et al. 2022

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Direkte C−H‐Funktionalisierungen durch Elektrokatalyse werden dominiert durch die Verwendung stark koordinierender N(sp2)‐dirigierender Gruppen. Im Gegensatz dazu sind direkte elektrokatalytische Transformationen schwach koordinierender Phenole weitgehend unbekannt. Vor diesem Hintergrund wurden elektrooxidative peri‐C−H‐Alkenylierungen anspruchsvoller 1‐Naphthole durch die vielseitige Rhodium(III)‐Katalyse mit nutzerfreundlicher galvanostatischer Elektrolyse erreicht. Für die Rhodaelektrokatalyse wurden leicht verfügbare Alkene und ein protisches Reaktionsmedium verwendet. Die Methode zeichnet sich durch eine große Anwendungsbreite, eine gute Toleranz gegenüber funktionellen Gruppen und eine hohe Positions‐ und Stereoselektivität aus. Die Strategie wurde erfolgreich auf hochwertige, stickstoffhaltige Heterocyclen angewandt, wodurch ein direkter Zugang zu ungewöhnlichen heterocyclischen Motiven auf der Grundlage des Dihydropyranochinolingerüsts geschaffen wurde.

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Rhodaelectro‐Catalyzed peri‐Selective Direct Alkenylations with Weak O‐Coordination Enabled by the Hydrogen Evolution Reaction (HER)

et al. 2022

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Direct CÀ H functionalizations by electrocatalysis is dominated by strongly coordinating N(sp 2 )directing groups. In sharp contrast, direct electrocatalytic transformations of weakly-coordinating phenols remain underdeveloped. Herein, electrooxidative peri CÀ H alkenylations of challenging 1-naphthols were achieved by versatile rhodium(III) catalysis via userfriendly constant current electrolysis. The rhodaelectrocatalysis employed readily-available alkenes and a protic reaction medium and features ample scope, good functional group tolerance and high site-and stereoselectivity. The strategy was successfully applied to high-value, nitrogen-containing heterocycles, thereby providing direct access to uncommon heterocyclic motifs based on the dihydropyranoquinoline skeleton.

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Efficient oxidative dimerization of 1-naphthols to 2,2′-binaphthyls with dioxygen mediated by semiconductors

Cited by 17 publications

References 25 publications

Oxidative Coupling of 1‐Naphthols over Noble and Base Metal Catalysts

Oxidative Coupling of 1‐Naphthols over Noble and Base Metal Catalysts

Rhodaelektro‐katalysierte peri‐selektive direkte Alkenylierungen mit schwacher O‐Koordination ermöglicht durch die Wasserstoffbildungsreaktion (HER)

Rhodaelectro‐Catalyzed peri‐Selective Direct Alkenylations with Weak O‐Coordination Enabled by the Hydrogen Evolution Reaction (HER)

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