Transition‐Metal‐Free α‐Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process

Drapeau, Martin Pichette; Fabre, Indira; Grimaud, Laurence; Ciofini, Ilaria; Ollevier, Thierry; Taillefer, Marc

doi:10.1002/ange.201502332

Cited by 44 publications

(2 citation statements)

References 54 publications

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“…10, the apparent activation energy ( E a ) and the activation entropy (Δ S 0* ) are determined to be 15.21 kJ mol −1 and −232.8 J mol −1 K −1 , respectively, according to transition state theory. The low E a value is reflected by the high negative Δ S 0* , indicating a significant change in the mobility of the reactant going from the initial to the activated state and maybe related to the radical-involved reaction [ 47 , 48 ].…”

Section: Resultsmentioning

confidence: 99%

Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Zhao

Cao

Duan

et al. 2020

National Science Review

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The functionalization of otherwise unreactive C–H bonds adds a new dimension to synthetic chemistry, yielding useful molecules for a range of applications. Arylation has emerged as an increasingly viable strategy for functionalization of heteroarenes which constitute an important class of structural moieties for organic materials. However, direct bisarylation of heteroarenes to enable aryl-heteroaryl-aryl bond formation remains a formidable challenge, due to the strong coordination between heteroatom of N or S and transitional metals. Here we report Pd interstitial nanocatalysts supported on ordered mesoporous carbon as catalysts for a direct and highly efficient bisarylation method for five-membered heteroarenes that allows for green and mild reaction conditions. Notably, in the absence of any base, ligands, and phase transfer agents, high activity (turn-over frequency, TOF up to 107 h−1) and selectivity (> 99%) for the 2,5-bisarylation of five-membered heteroarenes are achieved in water. A combination of characterization reveals that the remarkable catalytic reactivity here is attributable to the parallel adsorption of heteroarene over Pd clusters, which breaks the barrier to electron transfer in traditional homogenous catalysis and creates dual electrophilic sites for aryl radicals and adsorbate at C2 and C5 positions. The d-band filling at Pd sites shows a linear relationship with activation entropy and catalytic activity. The ordered mesopores facilitate the absence of a mass transfer effect. These findings suggest alternative synthesis pathways for the design, synthesis and understanding of a large number of organic chemicals by ordered mesoporous carbon supported palladium catalysts.

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Section: Resultsmentioning

confidence: 99%

Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Zhao

Cao

Duan

et al. 2020

National Science Review

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“…Recently, a number of methods for stereoselective synthesis of tri- and tetrasubstituted alkenes were reported, but it is hard to control the chemo- and regioselectivity of products. According to previous studies, , ( Z )-vinylic sulfides 3 are important intermediates in the preparation of tri- and tetrasubstituted alkenes.…”

Section: Resultsmentioning

confidence: 99%

Nickel-Catalyzed Regioselective Cleavage of C_sp²–S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes

Chen

et al. 2016

J. Org. Chem.

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We describe here an efficient route for the synthesis of (Z)-vinylic sulfides 3 via the highly regio- and stereoselective coupling of (Z)-1,2-bis(aryl(alkyl)thio)alkenes and Grignard reagents over a Ni catalyst under mild conditions. (Z)-Vinylic sulfides 3 are important intermediates in the synthesis of tri- and tetrasubstituted alkenes that are important construction blocks for drugs and natural products. The directing organosulfur groups (SR) can be converted to diaryl(alkyl) disulfides (RSSR) using H2O2 as oxidant, hence avoiding the waste of sulfur resources. The protocol provides a general method that is highly regio- and stereoselective for the synthesis of a diversity of tri- and tetrasubstituted alkenes.

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Concise Synthesis of 4‐Arylquinolines via Intramolecular Cyclization of Allylamines and Ketones

Wei

Cheng

et al. 2015

Adv Synth Catal

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Thei ntramolecular cyclization of allylamines and ketones was achieved in the presence of potassium tert-butoxide and N,N-dimethylformamide.As eries of 4-arylquinolines was prepared in good yields.T he reactionc ould be accomplisheda t room temperature using only as ubstoichiometric amount of potassium tert-butoxide.O nt he other hand, the reactiono ft he structurallya nalogous allyl ethers affordedd iverse products.T he reaction may proceed via the rearrangement of a-aminoallyl radicals and the generation of nucleophilic enamine intermediates.T his findingr epresents an ew strategy for the synthesis of quinoline derivatives from readily available 2-(allylamino)phenyl ketones.Scheme 1. Reactions of substrates 1s-1v.Scheme2.Te ntative reaction mechanism. 3476 asc.wiley-vch.de

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Transition‐Metal‐Free α‐Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process

Cited by 44 publications

References 54 publications

Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Nickel-Catalyzed Regioselective Cleavage of C_sp²–S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes

Concise Synthesis of 4‐Arylquinolines via Intramolecular Cyclization of Allylamines and Ketones

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Transition‐Metal‐Free α‐Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process

Cited by 44 publications

References 54 publications

Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Nickel-Catalyzed Regioselective Cleavage of Csp2–S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes

Concise Synthesis of 4‐Arylquinolines via Intramolecular Cyclization of Allylamines and Ketones

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Nickel-Catalyzed Regioselective Cleavage of C_sp²–S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes