Ligand and base-free Heck reaction with heteroaryl halides

Kantam, M. Lakshmi; Reddy, P. Vishnuvardhan; Srinivas, P.; Bhargava, Suresh K.

doi:10.1016/j.tetlet.2011.06.081

Cited by 20 publications

(3 citation statements)

References 54 publications

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“…The procedure yielded 870 mg (47 %) of the title compound as a pale‐yellow solid. Spectral data is consistent with the literature [52] . 1 H NMR (400 MHz, CDCl 3 ) δ 7.50 – 7.45 (m, 2H), 7.35 (dd, J =8.4, 6.9 Hz, 2H), 7.28 – 7.17 (m, 3H), 7.10 – 6.99 (m, 2H), 6.94 (d, J =16.0 Hz, 1H).…”

Section: Methodssupporting

confidence: 91%

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Metal‐Free Transfer C−H Borylation of Substituted Thiophenes

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Desrosiers

Gaudy

et al. 2023

Zeitschrift anorg allge chemie

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Thiophenes are crucial chemical building blocks in the fields of medicinal and material chemistry. As such, the CÀ H functionalization of these units is of key importance for developing novel applications. Herein, we report the CÀ H borylation of thiophenes using metal-free transfer CÀ H borylation. When performed on C2-substituted thiophenes, the reaction is selective for the borylation on C5, while C3-substituted thiophenes are borylated on C2, a complementary selectivity from reported CÀ H borylation approaches that typically prefer to borylate at the C5 position. An optimization of the catalytic system was performed. The reaction was shown to work with electronically diverse thiophenes and was also compatible with sensitive functional groups. Computational investigation of the reaction mechanism suggests a Lewis pair CÀ H activation mechanism with a selectivity that is kinetically driven. The methodology developed herein is an economical pathway for the preparation of C2-borylated C3-substituted thiophenes.

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Section: Methodssupporting

confidence: 91%

“…Spectral data is consistent with the literature. [52] 1 H NMR (400 MHz, CDCl 3 ) δ 7.50 -7.45 (m, 2H), 7.35 (dd, J = 8.4, 6.9 Hz, 2H), 7.28 -7.17 (m, 3H), 7.10 -6.99 (m, 2H), 6.94 (d, J = 16.0 Hz, 1H).…”

Section: -(35-dimethoxyphenyl)-13-dihydro-2h-imidazole-2-thione (1 C)mentioning

confidence: 99%

Metal‐Free Transfer C−H Borylation of Substituted Thiophenes

Fontaine

Desrosiers

Gaudy

et al. 2023

Zeitschrift anorg allge chemie

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“…Nevertheless, the asymmetric Heck reaction of N ‐heteroaryl halides and heterocyclic alkenes has been an unsolved problem and scarce examples were included in these previous reports. The key issue is the strong coordinating ability of N ‐heteroaryl substrates in particular pyridyl halides to transition metal resulting in catalyst deactivation with low or no activities, [15a] which has significantly impeded the development of robust Heck reaction protocols tolerating N ‐heteroaryl halide substrates [15b–e] . To address this challenge, we hypothesized that the employment of a sterically bulky P, P=O ligand [16] could be a solution for the Heck reaction of N ‐heteroaryl halides with the following considerations (Figure 2b): 1) The steric bulk would create coordinative unsaturation and inhibit the formation of fully coordinated inactive palladium species; 2) The hemilabile character of the P, P=O ligand enables ready release of a coordination site of Pd II complex after oxidative addition, allowing facile coordination of the alkene substrate to proceed the ensuring insertion process.…”

Section: Introductionmentioning

confidence: 99%

Heck Reaction of N‐Heteroaryl Halides for the Concise Synthesis of Chiral α‐Heteroaryl‐substituted Heterocycles

Luo

Yang

et al. 2022

Angewandte Chemie

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The Heck reaction between N-heteroaryl halides and heterocyclic alkenes provides a convenient approach to biologically relevant α-heteroaryl functionalized heterocycles, yet reactions of this type have been challenging due to strong N-heteroaryl coordination to palladium metal, which causes catalyst poisoning. In this report, an efficient palladium-catalyzed Heck reaction between N-heteroaryl halides and heterocyclic olefins is established, leading to a variety of α-heteroaryl substituted heterocycles. The method features an unprecedented broad substrate scope and excellent functional group compatibility. The employment of a sterically bulky P, P=O ligand containing an anthryl moiety is crucial for this transformation due to the coordinative unsaturation facilitated by its steric bulkiness. The asymmetric variant of the Heck reaction is achieved with (S)-DTBM-SEGPHOS via a cationic palladium pathway, which has enabled an efficient asymmetric synthesis of (S)-nicotine and its analogues.

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Heck Reaction of N‐Heteroaryl Halides for the Concise Synthesis of Chiral α‐Heteroaryl‐substituted Heterocycles

Luo

Yang

et al. 2022

Angew Chem Int Ed

View full text Add to dashboard Cite

The Heck reaction between N‐heteroaryl halides and heterocyclic alkenes provides a convenient approach to biologically relevant α‐heteroaryl functionalized heterocycles, yet reactions of this type have been challenging due to strong N‐heteroaryl coordination to palladium metal, which causes catalyst poisoning. In this report, an efficient palladium‐catalyzed Heck reaction between N‐heteroaryl halides and heterocyclic olefins is established, leading to a variety of α‐heteroaryl substituted heterocycles. The method features an unprecedented broad substrate scope and excellent functional group compatibility. The employment of a sterically bulky P, P=O ligand containing an anthryl moiety is crucial for this transformation due to the coordinative unsaturation facilitated by its steric bulkiness. The asymmetric variant of the Heck reaction is achieved with (S)‐DTBM‐SEGPHOS via a cationic palladium pathway, which has enabled an efficient asymmetric synthesis of (S)‐nicotine and its analogues.

show abstract

Ligand and base-free Heck reaction with heteroaryl halides

Cited by 20 publications

References 54 publications

Metal‐Free Transfer C−H Borylation of Substituted Thiophenes

Metal‐Free Transfer C−H Borylation of Substituted Thiophenes

Heck Reaction of N‐Heteroaryl Halides for the Concise Synthesis of Chiral α‐Heteroaryl‐substituted Heterocycles

Heck Reaction of N‐Heteroaryl Halides for the Concise Synthesis of Chiral α‐Heteroaryl‐substituted Heterocycles

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