Lewis Acid Assisted Nickel‐Catalyzed Cross‐Coupling of Aryl Methyl Ethers by C−O Bond‐Cleaving Alkylation: Prevention of Undesired β‐Hydride Elimination

Liu, Xiangqian; Hsiao, Chien‐Chi; Kalvet, Indrek; Leiendecker, Matthias; Guo, Lin; Schoenebeck, Franziska; Rueping, Magnus

doi:10.1002/anie.201510497

Cited by 139 publications

(74 citation statements)

References 81 publications

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“…However, this breakthrough was overlooked for decades, until quite recently. After the development of improved conditions, ArOR can now be used as a coupling partner in several types of transition metal (TM)-catalyzed cross-couplings and related transformations, such as Suzuki-Miyaura-type (B), [24][25][26][27][28][29][30][31] Negishi-type (Zn or Al), [32][33][34][35][36] Murahashi-type (Li), [37][38][39][40] and other reactions. [41][42][43][44][45][46][47][48][49][50] As a continuation of our work in this area, we reported in 2012 the first ethereal Negishi-type coupling of aryl alkyl ether 36) (Chart 1(1)) and in 2016 we reported a systematic examination of ethereal Murahashi-type reaction 37) (Chart 1(2)).…”

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confidence: 99%

Ethereal C–O Bond Cleavage Mediated by Ni(0)-Ate Complex: A DFT Study

et al. 2017

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Density functional theory calculations were performed to explore the mechanism of Ni-catalyzed crosscoupling reactions involving organo-lithium and -zinc reagents through ethereal C-O bond cleavage. Based on this work, together with our previous mechanistic study on etheric Kumada-Tamao reaction, we identify and characterize a novel catalytic cycle for cross-coupling mediated by Ni(0)-ate complex.Key words cross-coupling; ether; nickel catalyst; organolithium; organozinc; density functional theory (DFT) calculation Efficient and selective cleavage and transformation of C-O bonds, particularly by means of cross-coupling methods, has attracted great interest, since compounds containing C-O moieties occur widely in nature and are also extensively utilized in industry.1-8) Among C-O compounds, ethers are particularly attractive, [1][2][3][4][5][6][7][8] as they offer the advantages of 1) high atom economy/conversion efficiency (the use of ethers as simple as MeO as substrates affords fewer by-products compared with tosylate, mesylate, triflate, phosphate, etc.), 2) environmental compatibility (cleavage of the C-O moiety in ether releases non-halogen-containing waste), and 3) excellent stability, easy accessibility and wide diversity. However, ethereal C-O bonds ( E C-O) are very unreactive, and most of the well-established Pd-catalyzed C-O bond-cleaving protocols are ineffective for ethers.On the other hand, Ni-catalysts have proved effective for many types of C-O bond cleavage, including ethers. As early as in 1979, Wenkert et al. 9,10) reported the first Ni-catalyzed Kumada-Tamao type (Mg) 9-23) reaction, in which aryl methyl ether (ArOMe) acted as the electrophilic partner, and this is now recognized as the first example of Ni-catalyzed activation of an inert C-O bond. However, this breakthrough was overlooked for decades, until quite recently. After the development of improved conditions, ArOR can now be used as a coupling partner in several types of transition metal (TM)-catalyzed cross-couplings and related transformations, such as Suzuki-Miyaura-type (B), [24][25][26][27][28][29][30][31] Negishi-type (Zn or Al), [32][33][34][35][36] Murahashi-type (Li), [37][38][39][40] and other reactions. 41-50) As a continuation of our work in this area, we reported in 2012 the first ethereal Negishi-type coupling of aryl alkyl ether 36) (Chart 1(1)) and in 2016 we reported a systematic examination of ethereal Murahashi-type reaction 37) (Chart 1(2)). More recently, we also reported an in-depth study of Ni-catalyzed cross-coupling between organoaluminums and various types of C-O electrophiles, including aryl alkyl ether. 32) Results and DiscussionThe conventional catalytic cycle for cross-coupling reaction consists of three elemental steps: oxidative addition (OA), transmetalation, and reductive elimination. [51][52][53][54] Martin and colleagues reported that direct OA of a E C-O bond to Ni(0) requires high temperature, based on experimental and theoretical findings.46) Computational studies by Nakamura and colleagues, ...

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confidence: 99%

Ethereal C–O Bond Cleavage Mediated by Ni(0)-Ate Complex: A DFT Study

et al. 2017

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“…With respect to the mechanism responsible for C-O bond activation, there are also a number of opportunities to expand our knowledge base, in particular from an experimental standpoint such as the isolation of key intermediates [7,121]. Continued efforts promise to definitely improve this infant but promising method (after the submission of this manuscript, two methods for the alkylation of anisole substrates have appeared [122,123]). …”

Section: Discussionmentioning

confidence: 99%

Nickel-Catalyzed Cross-Coupling Reactions of Unreactive Phenolic Electrophiles via C–O Bond Activation

2016

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Nickel-catalyzed cross-coupling reactions of aryl esters, carbamates, carbonates, ethers and arenols are reviewed. Carbon-oxygen bonds in these phenol derivatives cannot be activated by palladium, a typical cross-coupling catalyst, but a low valent nickel species in conjunction with a strong σ-donor ligand is uniquely effective for achieving this. The review is organized primarily by substrate class and secondarily by coupling partners, encompassing organometallics, heteroatom nucleophiles, C-H bonds and many others. Although the reactions in this category are covered thoroughly, each reaction is described only briefly, so that it is possible to quickly overview the spectrum of nickel-catalyzed cross-coupling reactions of inert phenol derivatives. The robustness of inert phenol derivatives under typically used catalytic conditions as well as their utility as a directing group allow unique synthetic applications of these new C-O cross-coupling reactions, which is also included in cases where appropriate. Mechanistic aspects of C-O bond activation by nickel are also summarized, highlighting their diversity compared with the C-X bond activation involved in conventional cross-coupling processes.

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“…By utilizing the amination method optimized above, selective coupling of the silyloxy group,l eaving the aryl methyl ether intact, was illustrated in the conversion of 17 to 18 (Scheme 2). Alternatively,b eginning with the same starting material 17 under similar reaction conditions,but following the method developed by Rueping, [19] produced 19 in high yield, leaving the silyloxyarene functionality untouched. Next, coupling of the silyloxyarene product (19), utilizing the silyloxyarene amination method, resulted in product 20 in high yield.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…Alternatively,b eginning with the same starting material 17 under similar reaction conditions,but following the method developed by Rueping, [19] produced 19 in high yield, leaving the silyloxyarene functionality untouched. Next, coupling of the silyloxyarene product (19), utilizing the silyloxyarene amination method, resulted in product 20 in high yield. Alternatively,t he same product can be accessed by utilizing the aryl methyl ether compound 18 and triethylaluminum.…”

Section: Angewandte Chemiementioning

confidence: 99%

Nickel‐Catalyzed Amination of Silyloxyarenes through C–O Bond Activation

Wiensch

Montgomery

2018

Angew Chem Int Ed

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Silyloxyarenes were utilized as electrophilic coupling partners with amines in the synthesis of aniline derivatives. A diverse range of amine substrates were used, including cyclic or acyclic secondary amines, secondary anilines, and sterically hindered primary anilines. Additionally, a range of sterically hindered and unhindered primary aliphatic amines were employed, which have previously been challenging with other classes of aryl ether electrophiles. Orthogonal couplings of silyloxyarenes with aryl methyl ethers are illustrated, where selectivity between the two C-O electrophiles is determined by ligand control, thereby allowing complementary and selective late-stage diversification of either electrophile. Finally, a sequential coupling displays the utility of this amination method along with the reversal in intrinsic reactivity between aryl methyl ethers and silyloxyarenes.

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Lewis Acid Assisted Nickel‐Catalyzed Cross‐Coupling of Aryl Methyl Ethers by C−O Bond‐Cleaving Alkylation: Prevention of Undesired β‐Hydride Elimination

Cited by 139 publications

References 81 publications

Ethereal C–O Bond Cleavage Mediated by Ni(0)-Ate Complex: A DFT Study

Ethereal C–O Bond Cleavage Mediated by Ni(0)-Ate Complex: A DFT Study

Nickel-Catalyzed Cross-Coupling Reactions of Unreactive Phenolic Electrophiles via C–O Bond Activation

Nickel‐Catalyzed Amination of Silyloxyarenes through C–O Bond Activation

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