Facile p-toluenesulfonic acid-promoted para-selective monobromination and chlorination of phenol and analogues

Bovonsombat, Pakorn; Ali, Rameez; Khan, Chiraphorn; Leykajarakul, Juthamard; Pla‐on, Kawin; Aphimanchindakul, Suraj; Pungcharoenpong, Natchapon; Timsuea, Nisit; Arunrat, Anchalee; Punpongjareorn, Napat

doi:10.1016/j.tet.2010.06.041

Cited by 49 publications

(25 citation statements)

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“…Thus, the proposed synthetic effort was started with the bromination of guaiacol ( 16 ) using NBS/PTSA to obtain aryl bromide ( 17 ) in 88 % yield. [8a] It was then benzylated to prepare the corresponding benzyl protected aryl bromide ( 18 ) in 76 % yield. [8b] This bromide ( 18 ) was further used in the preparation of triarylbismuth reagent ( TAB‐1 ) through lithiation and reaction with bismuth trichloride.…”

Section: Resultsmentioning

confidence: 99%

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Rapid Bis‐Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step‐economic Convergent Synthesis of Quebecol

2020

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The cross‐coupling study of gem‐dibromoesters with triarylbismuths as threefold arylating reagents was investigated under palladium‐catalyzed conditions. This study using triarylbismuth reagents explored the cross‐coupling reactivity with various functionalized gem‐dibromoesters. It furnished a variety of multi‐functional trisubstituted acrylates embedded with aryl, alkene and alkyne scaffolds in high yields. The present study in turn, provided easy access to various triarylated acrylates and functionalized 1,3‐dienyl and 1,3‐enyne esters. Further, the established method applied in the step‐economic and convergent synthesis of quebecol natural product in good yield.

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Section: Resultsmentioning

confidence: 99%

“…[8a] It was then benzylated to prepare the corresponding benzyl protected aryl bromide ( 18 ) in 76 % yield. [8b] This bromide ( 18 ) was further used in the preparation of triarylbismuth reagent ( TAB‐1 ) through lithiation and reaction with bismuth trichloride. This afforded triarylbismuth reagent ( TAB‐1 ) in 64 % yield (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Rapid Bis‐Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step‐economic Convergent Synthesis of Quebecol

2020

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“…Because electronwithdrawing groups decreased the reactivity of the attached phenyl ring for the electrophilic substitution of Br 2 , compound 1 in the photodecomposed CH 2 Br 2 solution might decrease the electron density of the phenyl ring through weak interactions of the alkoxide group with H + ions. [34] On the other hand, dibrominated stilbene (10Br 2 ) in the photodecomposed CH 2 Br 2 likely accelerated the structural rearrangement from meso-10Br 2 into a thermally stable rac-10Br 2 in the presence of HBr. [35] Bromination Reactions with HBr in Photodecomposed CH 2 Br 2…”

Section: Control Bromination Reactions With Elemental Brmentioning

confidence: 99%

Brominated Methanes as Photoresponsive Molecular Storage of Elemental Br₂

Kawakami

Tsuda

2012

Chemistry An Asian Journal

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The photochemical generation of elemental Br2 from brominated methanes is reported. Br2 was generated by the vaporization of carbon oxides and HBr through oxidative photodecomposition of brominated methanes under a 20 W low‐pressure mercury lamp, wherein the amount and situations of Br2 generation were photochemically controllable. Liquid CH2Br2 can be used not only as an organic solvent but also for the photoresponsive molecular storage of Br2, which is of great technical benefit in a variety of organic syntheses and in materials science. By taking advantage of the in situ generation of Br2 from the organic solvent itself, many organobromine compounds were synthesized in high practical yields with or without the addition of a catalyst. Herein, Br2 that was generated by the photodecomposition of CH2Br2 retained its reactivity in solution to undergo essentially the same reactions as those that were carried out with solutions of Br2 dissolved in CH2Br2 that were prepared without photoirradiation. Furthermore, HBr, which was generated during the course of the photodecomposition of CH2Br2, was also available for the substitution of the OH group for the Br group and for the preparation of the HBr salts of amines. Furthermore, the photochemical generation of Br2 from CH2Br2 was available for the area‐selective photochemical bleaching of natural colored plants, such as red rose petals, wherein Br2 that was generated photochemically from CH2Br2 was painted onto the petal to cause radical oxidations of the chromophoric anthocyanin molecules.

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“…21 This first foray in to bromination again used harsh conditions described by Saiganesh et al e.g. 23 Adopting a similar methodology, utilizing H 2 SO 4 instead of PTSA, led to the synthesis of 3e, 3g, and 3h, all in good yields. 22 Adopting this methodology, 3b and 3d were synthesized (Table 2) and we were able to acquire a single crystal X-ray diffraction structure of 3b (Fig.…”

Section: Introductionmentioning

confidence: 99%

Regioselective routes to orthogonally-substituted aromatic MIDA boronates

Kemmitt

Roe

et al. 2016

Org. Biomol. Chem.

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A series of tetrasubstituted aromatics has been synthesized, many of which are based on elaborated N-methyliminodiacetic acid (MIDA)-boronates. A sequence employing nitration, bromination, stepwise Suzuki-Miyaura (SM) coupling with a boronic acid, then base-mediated unmasking of the boronic acid from the MIDA-boronate and a second SM-coupling has led to our desired, mainly 1,2,4,5-substituted tetrasubstituted aromatic targets.

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Facile p-toluenesulfonic acid-promoted para-selective monobromination and chlorination of phenol and analogues

Cited by 49 publications

References 50 publications

Rapid Bis‐Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step‐economic Convergent Synthesis of Quebecol

Rapid Bis‐Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step‐economic Convergent Synthesis of Quebecol

Brominated Methanes as Photoresponsive Molecular Storage of Elemental Br₂

Regioselective routes to orthogonally-substituted aromatic MIDA boronates

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Facile p-toluenesulfonic acid-promoted para-selective monobromination and chlorination of phenol and analogues

Cited by 49 publications

References 50 publications

Rapid Bis‐Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step‐economic Convergent Synthesis of Quebecol

Rapid Bis‐Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step‐economic Convergent Synthesis of Quebecol

Brominated Methanes as Photoresponsive Molecular Storage of Elemental Br2

Regioselective routes to orthogonally-substituted aromatic MIDA boronates

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Product

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Brominated Methanes as Photoresponsive Molecular Storage of Elemental Br₂