Regiocontroled Pd-catalysed C5-arylation of 3-substituted thiophene derivatives using a bromo-substituent as blocking group

Brahim, Mariem; Ammar, Houcine; Soulé, Jean‐François

doi:10.3762/bjoc.12.210

Cited by 10 publications

(6 citation statements)

References 36 publications

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“…Similarly, from 3-bromothiophene, the formation of a mixture of C5 and C2 regioisomers is observed. Notably, palladium-catalyzed C–H arylation of bromothiophenes also affords a mixture of regioisomers . The authors proposed a mechanism where eosin Y replaces [Ru(bipy) 3 ] 2+ as an organic photoredox catalyst.…”

Section: Photocatalyzed Arylation Of C(sp2)–h Bondsmentioning

confidence: 99%

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Photoredox Catalysis for Building C–C Bonds from C(sp²)–H Bonds

2018

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Transition metal-catalyzed C-H bond functionalizations have been the focus of intensive research over the last decades for the formation of C-C bonds from unfunctionalized arenes, heteroarenes, alkenes. These direct transformations provide new approaches in synthesis with high atom- and step-economy compared to the traditional catalytic cross-coupling reactions. However, such methods still suffer from several limitations including functional group tolerance and the lack of regioselectivity. In addition, they often require harsh reaction conditions and some of them need the use of strong oxidant, in a stoichiometric amount, avoiding these processes to be truly eco-friendly. The use of photoredox catalysis has contributed to a significant expansion of the scope of C(sp)-H bond functionalizations which include the direct arylations, (perfluoro)alkylations, acylations, and even cyanations. Most of these transformations involve the photochemical induced generation of a radical followed by its regioselective addition to arenes, heteroarenes, or alkenes, leading to the building of a new C(sp)-C bond. The use of photoredox catalysis plays crucial roles in these reactions promoting electron transfer, enabling the generation of radical species and single electron either oxidation or reduction. Such reactions operating at room temperature allow the building of C-C bonds with high chemo-, regio-, or stereoselectivity. This review surveys the formation of C(sp)-C bonds initiated by photoredox catalysis which involves a C(sp)-H bond functionalization step, describes the advantages compared to traditional C(sp)-H bond functionalizations, and presents mechanistic insights into the role played by the photoredox catalysts.

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Section: Photocatalyzed Arylation Of C(sp2)–h Bondsmentioning

confidence: 99%

“…Notably, palladium-catalyzed C− H arylation of bromothiophenes also affords a mixture of regioisomers. 63 The authors proposed a mechanism where eosin Y replaces [Ru(bipy) 3 ] 2+ as an organic photoredox catalyst.…”

Section: Chemical Reviewsmentioning

confidence: 99%

Photoredox Catalysis for Building C–C Bonds from C(sp²)–H Bonds

2018

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“…Several reaction conditions such as the nature of the catalyst, − carboxylic acid additive, − ligand system, − solvent, , and base . Small molecule analysis was among the first ways DHAP was investigated, and remains a useful tool. − In this study, we investigated all these elements using model polymers in order to obtain reaction conditions that yield high quality polythiophene derivatives.…”

Section: Introductionmentioning

confidence: 99%

Toward Defect Suppression in Polythiophenes Synthesized by Direct (Hetero)Arylation Polymerization

2023

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In this study, we have investigated different reaction conditions for defect suppression in polythiophene derivatives synthesized by direct (hetero)arylation polymerization (DHAP). The well-known PQT12 polymer was used as a model due to its simple structure which facilitated analysis. 2-Bromo-3,4′-didodecyl-2:2′,5′:2″,5″:2‴-quaterthiophene and 2-bromo-3″,4‴-didodecyl-2:2′,5′:2″,5″-2‴-quaterthiophene monomers allowed the analysis of both homocoupling defects and β-branching defects due to their asymmetric structure as well as the effect of β-protection. The properties of the resulting polymers were analyzed using sizeexclusion chromatography, differential scanning calorimetry, UV− visible absorption spectroscopy, and 1 H NMR spectrometry. Some model compounds were synthesized to help with end-groups analysis, revealing debromination as the main obstacle to chain growth. The highest quality polymer was obtained when using toluene as a solvent, Pd 2 dba 3 as a palladium(0) catalyst, neo-decanoic acid (NDA) as a carboxylic acid additive, and a dual-ligand system with diamine TMEDA and phosphine P(o-OMePh) 3 . This study also revealed the importance of the choice of the monomers for the preparation of well-defined conjugated polymers.

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“…23 The C2 position of the thiophene/furan ring can be blocked to synthesize C5 selective monoaryl products, followed by latestage sequential arylation at C2 (Scheme 5 showed that the C2−Br substituent on thiophene, 18, allows for temperature-controlled sequential arylation at C5, followed by C2 arylation. 24 A lower temperature (80 °C) was required to avoid oxidative addition at C2−Br. The second arylation at C2 occurred with direct (hetero)arylation or SMC reactions to afford 20.…”

Section: Introductionmentioning

confidence: 99%

Strategic Advances in Sequential C-Arylations of Heteroarenes

et al. 2020

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Sequence-specific C-arylation strategies have important applications in medicinal and material research. These strategies allow C–C bond formations in a regioselective manner to synthesize large molecular libraries for studying structure–activity profiles. The past decade has seen the development of single C–C bond forming reactions using various transition-metal catalysts, cryogenic metalation strategies, and metal-free methods. Sequential arylations of heterocycles allow for the formation of multiaryl derivatives and are a preferred choice over de novo synthetic routes. This perspective sheds light on recent strategic advances to develop various sequential synthetic routes for the multiarylation of heteroarenes. This perspective addresses many challenges in optimizing sequential routes with respect to catalysts, reaction parameters, and various strategies adopted to obtain diversely arylated products.

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Regiocontroled Pd-catalysed C5-arylation of 3-substituted thiophene derivatives using a bromo-substituent as blocking group

Cited by 10 publications

References 36 publications

Photoredox Catalysis for Building C–C Bonds from C(sp²)–H Bonds

Photoredox Catalysis for Building C–C Bonds from C(sp²)–H Bonds

Toward Defect Suppression in Polythiophenes Synthesized by Direct (Hetero)Arylation Polymerization

Strategic Advances in Sequential C-Arylations of Heteroarenes

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Regiocontroled Pd-catalysed C5-arylation of 3-substituted thiophene derivatives using a bromo-substituent as blocking group

Cited by 10 publications

References 36 publications

Photoredox Catalysis for Building C–C Bonds from C(sp2)–H Bonds

Photoredox Catalysis for Building C–C Bonds from C(sp2)–H Bonds

Toward Defect Suppression in Polythiophenes Synthesized by Direct (Hetero)Arylation Polymerization

Strategic Advances in Sequential C-Arylations of Heteroarenes

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Product

Resources

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Photoredox Catalysis for Building C–C Bonds from C(sp²)–H Bonds

Photoredox Catalysis for Building C–C Bonds from C(sp²)–H Bonds