Enantioselective Addition of Pyrazoles to Dienes**

Jiu, Alexander Y.; Slocumb, Hannah S.; Yeung, Charles S.; Yang, Xiao‐Hui; Dong, Vy M.

doi:10.1002/ange.202105679

Cited by 10 publications

(1 citation statement)

References 41 publications

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“…In Path A, ionization of conjugate pyrazole in the presence of catalyst affords pyrazole anion through hydrogen bonding, which will attack the carbocation to release the product. On the other hand, pyrazole is considered as a soft nucleophile because the pKa of NH in pyrazole is about 19.8 [12e,f,29] . Therefore, VI or VII formed the hydrogen bonding effect with water and catalyst will act as the soft nucleophile and add directly to the allylic moiety to produce transition state IV shown in Path B.…”

Section: Resultsmentioning

confidence: 99%

Bu₄NHSO₄‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Zhuang

et al. 2021

Adv Synth Catal

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Allylic amines are valuable and functional building blocks. Direct N-allylation of pyrazole and its derivatives as an atom economic strategy to provide allylic amines has been achieved only using commercial Bu 4 NHSO 4 as the metal-free catalyst and water as the solvent without any additives. 11-93% isolated yields were obtained for the N-allylation of pyrazole and its derivatives with allylic alcohols. Bu 4 NHSO 4 could be reused for six times by simple extraction nearly without loss of catalytic activity and was also suitable for a gram-scale production. The reaction of allylic ether and pyrazole did not occur to give the desired product indicated that allylic ether was not the active intermediate in the pathway. Density functional theory (DFT) calculations reveal that there are hydrogen bonding effects among substrates, solvent and catalyst, especially the one formed between allylic alcohol and H 2 O. Control experiments in different protic solvents further demonstrate the intermolecular hydrogen bonding of allylic alcohol and water.

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Section: Resultsmentioning

confidence: 99%

Bu₄NHSO₄‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Zhuang

et al. 2021

Adv Synth Catal

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Umpolung Asymmetric 1,5‐Conjugate Addition via Palladium Hydride Catalysis

et al. 2022

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Electronically matched nucleophilic 1,6-conjugate addition has been well studied and widely applied in synthetic areas. In contrast, nucleophilic 1,5-conjugate addition represents an electronically forbidden process and is considered unfeasible. Here, we describe modular protocols for 1,5-conjugate addition reactions via palladium hydride catalysis. Both palladium and synergistic Pd/organocatalyst systems are developed to catalyze 1,5conjugate reaction, followed by inter-or intramolecular [3+2] cyclization. A migratory 1,5-addition protocol is established to corroborate the feasibility of this umpolung concept. The 1,5-addition products are conveniently transformed into a series of privileged enantioenriched motifs, including polysubstituted tetrahydrofuran, dihydrofuran, cyclopropane, cyclobutane, azetidine, oxetane, thietane, spirocycle and bridged rings. Preliminary mechanistic studies corroborate the involvement of palladium hydride catalysis.

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Stereodivergent Construction of Csp³−Csp³Bonds Bearing Vicinal Stereocenters by Synergistic Palladium and Phase‐Transfer Catalysis

et al. 2022

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Enantioselective Addition of Pyrazoles to Dienes**

Cited by 10 publications

References 41 publications

Bu₄NHSO₄‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Bu₄NHSO₄‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Umpolung Asymmetric 1,5‐Conjugate Addition via Palladium Hydride Catalysis

Stereodivergent Construction of Csp³−Csp³Bonds Bearing Vicinal Stereocenters by Synergistic Palladium and Phase‐Transfer Catalysis

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Enantioselective Addition of Pyrazoles to Dienes**

Cited by 10 publications

References 41 publications

Bu4NHSO4‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Bu4NHSO4‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Umpolung Asymmetric 1,5‐Conjugate Addition via Palladium Hydride Catalysis

Stereodivergent Construction of Csp3−Csp3Bonds Bearing Vicinal Stereocenters by Synergistic Palladium and Phase‐Transfer Catalysis

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Bu₄NHSO₄‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Bu₄NHSO₄‐Catalyzed Direct N‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System

Stereodivergent Construction of Csp³−Csp³Bonds Bearing Vicinal Stereocenters by Synergistic Palladium and Phase‐Transfer Catalysis