Nickel‐Catalyzed Hydroheteroarylation of Vinylarenes

Nakao, Yoshiaki; Kashihara, Natsuko; Kanyiva, Kyalo Stephen; Hiyama, Tamejiro

doi:10.1002/anie.201001470

Cited by 207 publications

(85 citation statements)

References 26 publications

(20 reference statements)

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“…[8g, [10][11][12] Thus, Hu and co-workers elegantly devised the nickel complex [( Me NN 2 )NiCl] bearing a tridentate pincer N 2 Nligand for direct functionalizations of heteroarenes with alkyl halides. [10] Unfortunately, the synthesis of this catalyst involves several reaction steps, which can limit its broader applications.…”

mentioning

confidence: 99%

User‐Friendly [(Diglyme)NiBr₂]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

2011

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A nitrogen and phosphorus ligand-free catalytic system derived from inexpensive [(di-A C H T U N G T R E N N U N G glyme)NiBr 2 ] allowed for efficient direct C À H bond alkylations of heteroarenes with unactivated b-hydrogen-containing alkyl halides under basic reaction conditions. Keywords: alkylation; azoles; C À H activation; heterocycles; mechanism; nickel Substituted heteroarenes are indispensable substructures of, among others, biologically active compounds and functional materials. [1][2][3] In particular, strategies relying on direct C À H bond functionalizations arguably constitute the most ecologically benign and economically attractive methods for their preparation. [4] In recent years, various transition metal catalysts were devised for versatile direct arylations, alkenylations or alkynylations of heteroarenes by cleavages of unreactive C À H bonds.[5] In contrast, direct alkylations of (hetero)arenes with unactivated alkyl halides under basic reaction conditions continue to be difficult, predominantly because these challenging electrophiles lead to undesired b-eliminations.[6] Remarkable recent progress was represented by efficient ruthenium [7] and palladium catalyzed [8] direct alkylations of (hetero)arenes.[6] On the contrary, direct alkylations with less expensive nickel catalysts [9] are scarce, and were thus far solely achieved with nickel complexes derived from tridentate nitrogen ligands. [8g,10-12] Thus, Hu and co-workers elegantly devised the nickel complex [( Me NN 2 )NiCl] bearing a tridentate pincer N 2 Nligand for direct functionalizations of heteroarenes with alkyl halides.[10] Unfortunately, the synthesis of this catalyst involves several reaction steps, which can limit its broader applications.[13] Moreover, four direct alkylations of benzothiazole were recently achieved with a nickel complex derived from the tridentate nitrogen ligand terpyridine.[8g] Within our research program directed towards the development of userfriendly and sustainable C À H bond functionalizations, [14] we developed a cost-effective nitrogen-and phosphorus ligand-free [15] free nickel catalyst for direct alkylations of heteroarenes, on which we wish to report herein.At the outset of our studies, we tested a diverse array of commercially available nickel precursors for the direct C À H bond functionalization of benzoxazole (1a) with alkyl iodide 2a as the electrophile, 2,2'-bipyridine (bpy, 4) as the ligand, and CuI [10] as cocatalyst (Table 1). Among different nickel sources, [(di- Table 1. Nickel precursors for the direct C À H bond alkyla-A C H T U N G T R E N N U N G tion.[a] Entry[Ni] 3aaA C H T U N G T R E N N U N G [(diglyme)NiBr 2 ] 61%[a] Reaction conditions: 1a (1.0 mmol), 2a (1.5 mmol), [Ni] (5.0 mol%), CuI (7.5 mol%), 4 (6.0 mol%), t-BuOLi (2.0 mmol), 1,4-dioxane (3.0 mL), 140 8C, 16 h; isolated yields.

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confidence: 99%

User‐Friendly [(Diglyme)NiBr₂]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

2011

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“…(Scheme 13B). 30 Computational studies by Shi and co-workers revealed that, after hydrometalation, secondary coordination of the Ni-center to the aryl moiety of the styrenic partner accelerates CC reductive elimination to the branched product.…”

Section: Branch-selective Alkene Hydroarylations In the Absence Of DImentioning

confidence: 99%

“…30 Ong and co-workers have shown that the Ni/IMes system can promote related hydroarylations of β-substituted styrenes, which are generated by in situ isomerization of allyl benzene precursors (Scheme 13C). 31 An alternate system developed by the Ong group employs a Ni-catalyst modified with a chelating NHC ligand for the branch-selective hydroarylation of styrenes with benzimidazoles.…”

Section: Branch-selective Alkene Hydroarylations In the Absence Of DImentioning

confidence: 99%

Branch Selective Murai-type Alkene Hydroarylation Reactions

Crisenza

Bower²

2016

Chem. Lett.

106

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There is significant interest in the development of CC bondforming methodologies that directly access challenging benzylic stereocenters. Predominantly, efforts have been focused on the development of enantiospecific or enantioselective crosscoupling methodologies. An alternate and conceptually ideal approach involves the development of branch-selective and enantioselective Murai-type alkene hydroarylations. Recent progress towards this broad, yet challenging goal is highlighted.

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“…In addition to iridium and cobalt catalysis, and following the work initiated by Cavell et al [138] on the alkylation of azolium salts, nickel-catalyzed alkylations of various heteroarenes (i.e., indoles [139], benzimidazoles [139], benzothiazoles [139], benzoxazoles [139] In addition, the selective C-4 alkylation of pyridines could be achieved through the use of sterically hindered NHC ligands and cooperative Lewis acids (Scheme 19.99) [142,143]. The best yields were obtained with the very bulky (2,6-t-Bu 2 -4-Me-C 6 H 2 O) 2 AlMe (MAD) aluminum reagent.…”

Section: Hydroarylation and Hydroalkenylation Of Alkenes 1481mentioning

confidence: 99%

CH Bond Alkylation (Including Hydroarylation of Alkenes)

Jean‐Gérard

Jazzar

Baudoin

2013

Metal‐Catalyzed Cross‐Coupling Reactions and More

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Nickel‐Catalyzed Hydroheteroarylation of Vinylarenes

Abstract: In the nickel of time: A nickel/carbene catalyst effects the hydroheteroarylation of vinylarenes to give 1,1‐diarylethanes that contain various heteroaryl moieties with excellent regioselectivity. EWG= electron‐withdrawing group.

Cited by 207 publications

References 26 publications

User‐Friendly [(Diglyme)NiBr₂]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

User‐Friendly [(Diglyme)NiBr₂]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

Branch Selective Murai-type Alkene Hydroarylation Reactions

CH Bond Alkylation (Including Hydroarylation of Alkenes)

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Nickel‐Catalyzed Hydroheteroarylation of Vinylarenes

Abstract: In the nickel of time: A nickel/carbene catalyst effects the hydroheteroarylation of vinylarenes to give 1,1‐diarylethanes that contain various heteroaryl moieties with excellent regioselectivity. EWG= electron‐withdrawing group.

Cited by 207 publications

References 26 publications

User‐Friendly [(Diglyme)NiBr2]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

User‐Friendly [(Diglyme)NiBr2]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

Branch Selective Murai-type Alkene Hydroarylation Reactions

CH Bond Alkylation (Including Hydroarylation of Alkenes)

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Resources

About

User‐Friendly [(Diglyme)NiBr₂]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages

User‐Friendly [(Diglyme)NiBr₂]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through CH Bond Cleavages