Silver-Catalyzed Regio- and Stereoselective Formal Carbene Insertion into Unstrained C−C σ-Bonds of 1,3-Dicarbonyls

Liu, Zhaohong; Zhang, Xinyu; Virelli, Matteo; Zanoni, Giuseppe; Anderson, Edward A.; Bi, Xihe

doi:10.1016/j.isci.2018.09.006

Cited by 38 publications

(19 citation statements)

References 40 publications

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“…[48][49][50][51] Furthermore, insertion into the C-H bonds of the alkane substrate is less electronically favored than the benzylic C-H bonds of the insertion products, 52 which usually leads to undesirable over-insertion. As part of our continued interest in the silver-catalyzed activation of diazo compounds, [53][54][55] here we report the realization of intermolecular C(sp 3 )-H insertions of donor carbenes into alkanes, employing Ntriftosylhydrazones as carbene sources together with electron-deficient silver ions and the weakly coordinating TpBr 3 ligand (Fig. 1b).…”

Section: Introductionmentioning

confidence: 99%

Site-Selective C–H Benzylation of Alkanes with N-Triftosylhydrazones Leading to Alkyl Aromatics

Liu

Cao

et al. 2020

Chem

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Alkanes are an abundant and valuable resource for transformation into value-added fine chemicals.However, selective functionalization of specific C(sp 3 )-H bonds in alkanes is a significant challenge, particularly for alkyl-alkyl bond formation, due to the small differences in reactivity between the various C(sp 3 )-H bonds in alkanes and their intrinsic inertness. Herein, we report a silver-catalyzed site-selective C(sp 3 )-H benzylation of simple alkanes using N-triftosylhydrazones as a convenient carbene precursor, which enables the synthesis of diverse array of alkylated aromatics. The reaction proceeds under mild conditions to afford high-value-added alkylarenes in generally high yields, with exquisite site selectivity and good functional group compatibility. A one-pot two-step protocol starting from aldehydes was also realized, thereby constituting a formal reductive alkylation of aryl aldehydes by alkanes. Experimental investigations and DFT calculations reveal that the role of the Tp Br3 Ag catalyst is threefold: it modulates the carbene reactivity, inhibits carbene dimerization, and avoids over-insertion of the product. All three aspects are crucial for the success of this first site-selective intermolecular insertion of donor carbenoids into C(sp 3 )-H bonds of simple alkanes. Methods Supporting InformationDetailed information about the experimental procedures as well as analytical data is provided in the Supplementary Information.

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Section: Introductionmentioning

confidence: 99%

Site-Selective C–H Benzylation of Alkanes with N-Triftosylhydrazones Leading to Alkyl Aromatics

Liu

Cao

et al. 2020

Chem

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“…On the other hand, sulfoxonium ylides are readily available and bench-stable carbene precursors, which have been extensively explored for the transition metal-catalyzed functionalization of C–H bonds 11. However, sulfoxonium ylide carbene-involved C–C bond functionalization has not yet been realized due to it being challenging to control the chemoselectivity from the same starting materials 12…”

Section: Introductionmentioning

confidence: 99%

Ruthenium(ii)-catalyzed chemoselective deacylative annulation of 1,3-diones with sulfoxonium ylides via C–C bond activation

Wen

et al. 2019

Chem. Sci.

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The first successful example of deacylative annulation of 1,3-diones with sulfoxonium ylides was achieved through Ru(II)-catalyzed C-C bond activation. The excellent chemoselectivity and broad substrate scope render this method a practical and versatile approach for the preparation of (hetero)aryl and alkenyl substituted furans, which are valuable units in many biologically active compounds and functional materials. A preliminary mechanistic study reveals that this process involves a deacylative a-ruthenation to generate key alkyl Ru(II) intermediates with the release of a benzoic acid fragment.Scheme 2 Scope of 1,3-diones. Reaction conditions: 1 (0.1 mmol), 2a (0.2 mmol), MesCO 2 Li (0.15 mmol), and [RuCl 2 (p-cymene)] 2 (5 mol%) in toluene (2 mL) at 120 C in air for 24 h. This journal isScheme 3 Scope of sulfoxonium ylides. Reaction conditions: 1a (0.1 mmol), 2 (0.2 mmol), MesCO 2 Li (0.15 mmol), and [RuCl 2 (p-cymene)] 2 (5 mol%) in toluene (2 mL) at 120 C in air for 24 h.Scheme 4 Gram-scale reactions and control experiments.9106 | Chem. Sci., 2019, 10, 9104-9108This journal is

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“…Interestingly, the carbenoid insertion (one-carbon insertion) product was not detected in any of the investigations of the reaction parameters 47 , 48 .…”

Section: Resultsmentioning

confidence: 97%

“…In 2018, Bi and co-workers reported the first example that involve the formal insertion of carbenoids into acyclic C(CO)−C bonds using Ag catalyst (Fig. 1c ) 47 , 48 . Undoubtedly, the development of multiple functional groups, particularly deriving from different molecules, and insertion into unstrained C(CO)−C bonds is of great interest from both practical synthetic applications and mechanistic investigations.…”

Section: Introductionmentioning

confidence: 99%

Rhodium(II)-catalyzed multicomponent assembly of α,α,α-trisubstituted esters via formal insertion of O–C(sp3)–C(sp2) into C–C bonds

Wen

Tian

et al. 2020

Nat Commun

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The direct cleavage of C(CO)−C single bonds, delivering otherwise inaccessible compounds, is a significant challenge. Although the transition metal-catalyzed insertion of functional groups into C(CO)−C bonds has been studied, strained ketone substrates or chelating assistance were commonly required. In this article, we describe a rhodium(II)-catalyzed three-component reaction of 1,3-diones, diazoesters, and N,N -dimethylformamide (DMF), leading to an unusual formal insertion of O–C(sp 3 )–C(sp 2 ) into unstrained C(CO)−C bonds. This procedure provides a rapid entry to a gamut of otherwise inaccessible α,α,α-trisubstituted esters/amide from relatively simple substrates in a straightforward manner. 55 examples of highly decorated products demonstrate the broad functional group tolerance and substrate scope. The combination of control experiments and isotope-labeling reactions support that O, C(sp 3 ), and C(sp 2 ) units derive from 1,3-diones, diazoesters, and DMF, respectively.

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Silver-Catalyzed Regio- and Stereoselective Formal Carbene Insertion into Unstrained C−C σ-Bonds of 1,3-Dicarbonyls

Cited by 38 publications

References 40 publications

Site-Selective C–H Benzylation of Alkanes with N-Triftosylhydrazones Leading to Alkyl Aromatics

Site-Selective C–H Benzylation of Alkanes with N-Triftosylhydrazones Leading to Alkyl Aromatics

Ruthenium(ii)-catalyzed chemoselective deacylative annulation of 1,3-diones with sulfoxonium ylides via C–C bond activation

Rhodium(II)-catalyzed multicomponent assembly of α,α,α-trisubstituted esters via formal insertion of O–C(sp3)–C(sp2) into C–C bonds

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