Transition-Metal-Catalyzed Direct Addition of Unactivated C–H Bonds to Polar Unsaturated Bonds

Yang, Lei; Huang, Hanmin

doi:10.1021/cr500610p

Cited by 689 publications

(138 citation statements)

References 363 publications

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“…122,123 In contrast to the functionalization of aromatic aldimines reported previously (Scheme 96), the vast majority of heteroaromatic aldimine C–H bond additions to isocyanates resulted in aminocarbonylation products 224 that did not undergo intramolecular cyclization in situ. While high yields of aminocarbonylated products with the N - tert -butyl aldimine intact could be observed by 1 H NMR, to facilitate isolation, an acidic work up to hydrolyze the imine was performed to obtain the corresponding aldehyde products 224 . Additions to both aryl and alkyl isocyanates proceeded smoothly, and selective C–H functionalization was achieved for a variety of heterocyclic aldimines, including for thiophene, furan, pyrrole, and indole derivatives.…”

Section: Isocyanatesmentioning

confidence: 99%

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

2016

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The transition metal-catalyzed addition of C–H bonds to carbonyls, imines and related polarized π-bonds has emerged as a particularly efficient and powerful approach for the construction of an incredibly diverse array of heteroatom substituted products. Readily available and stable inputs are typically employed, and reactions often proceed with very high functionality group compatibility and without the production of waste byproducts. Additionally, many transition metal-catalyzed C–H bond additions to polarized π-bonds occur within cascade reaction sequences to provide rapid access to a diverse array of different heterocyclic as well as carbocyclic products. This review highlights the diversity of transformations that have been achieved, catalysts that have been used, and types of products that have been prepared through the transition metal catalyzed addition of C–H bonds to carbonyls, imines and related polarized π-bonds.

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Section: Isocyanatesmentioning

confidence: 99%

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

2016

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“…Such C–H bond functionalization strategies are quite limited and most of the reported C–H activation-nucleophilic addition reactions utilize high-valence transition metal complexes such as Rh( iii ) for C–H bond activation. 7 In 2010, we reported the first example of such reaction, that is, rhodium-catalyzed direct carboxylation of 2-phenylpyridines. 8 In 2012, Yoshikai reported a catalytic C–H bond activation of 2-phenylpyridine derivatives using the combination of a cobalt catalyst and a stoichiometric organomagnesium reagent, followed by nucleophilic addition to N -arylimines.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic study of the rhodium-catalyzed carboxylation of simple aromatic compounds with carbon dioxide

et al. 2017

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“…1 Among the rich array of metal complexes that mediate C-H functionalization, Rh(III)-catalysts have proven to be exceptionally versatile due to their unique reactivity and high functional-group compatibility, 2 with additions of C(sp 2 )-H bonds to polarized π-bonds providing for convergent introduction of heteroatom functionality. [3][4][5][6][7][8][9] In this regard, we reported direct C(sp 2 )-H bond addition to isocyanates as a particularly step-and atomeconomic strategy for the preparation of aromatic, heterocyclic and alkenyl amides. 6f Direct C(sp 2 )-H bond additions to isocyanates have also been accomplished with Re 10 and Ru 11 catalysts.…”

Section: Introductionmentioning

confidence: 99%

Cobalt(III)-Catalyzed C–H Bond Amidation with Isocyanates

2015

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The first examples of cobalt(III)-catalyzed C-H bond addition to isocyanates are described, providing a convergent strategy for arene and heteroarene amidation. Using a robust air-and moisture-stable catalyst, this transformation demonstrates broad isocyanate scope, good functional-group compatibility and has been performed on gram scale. AbstractIn recent years, many elegant strategies employing transition-metal-catalyzed C-H bond functionalization have emerged for the synthesis of amines and nitrogen heterocycles. 1 Among the rich array of metal complexes that mediate C-H functionalization, Rh(III)-catalysts have proven to be exceptionally versatile due to their unique reactivity and high functional-group compatibility, 2 with additions of C(sp 2 )-H bonds to polarized π-bonds providing for convergent introduction of heteroatom functionality. [3][4][5][6][7][8][9] In this regard, we reported direct C(sp 2 )-H bond addition to isocyanates as a particularly step-and atomeconomic strategy for the preparation of aromatic, heterocyclic and alkenyl amides. 6f Direct C(sp 2 )-H bond additions to isocyanates have also been accomplished with Re 10 and Ru 11 catalysts. 12 In contrast, catalytic C-H bond functionalization with earth-abundant first-row transition-metals has emerged only recently, 13 and to our knowledge, additions to isocyanates have not been described. Herein we report the first examples of cobalt-catalyzed C-H bond amidation with isocyanates. [14][15] This convenient benchtop procedure is effective for multiple heterocycle directing groups, shows good functional group compatibility, broad scope for aromatic and alkyl isocyanates, and is readily scalable.For initial evaluation of Co(III)-catalyzed C-H bond additions to isocyanates, we chose 1-phenyl-1H-pyrazole (1a) and phenyl isocyanate (2a) as the coupling partners. First HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript developed by Kanai, Matsunaga, and co-workers for additions to sulfonyl imines 14p we anticipated that the cationic preformed catalyst [Cp*Co(C 6 H 6 )][PF 6 ] 2 (4a) might also facilitate C-H bond amidation with isocyanates. Indeed, the desired reactivity was achieved when catalyst 4a was utilized in the presence of catalytic potassium acetate at 80 °C, providing product 3a in 74% yield (Table 1, entry 1). Given that solvent effects have been observed to play a key role in obtaining optimal yield in Ru(II)-11 and Rh(III)-catalyzed C-H amidations, 6 different solvents were evaluated. While the use of the ethereal solvents 1,4-dioxane and tetrahydrofuran (entries 1 and 2, respectively) as well as 1,2-dichloroethane (entry 3) provided comparable yields, the non-polar and non-coordinating solvent toluene resulted in a low yield (entry 4). Ultimately, the higher boiling solvent 1,4-dioxane was selected for further reaction optimization because it allowed reactions to be conducted at higher temperatures.Performing the reaction at 120 °C rather than 80 °C moderately increased the yield (entries...

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Transition-Metal-Catalyzed Direct Addition of Unactivated C–H Bonds to Polar Unsaturated Bonds

Cited by 689 publications

References 363 publications

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

Mechanistic study of the rhodium-catalyzed carboxylation of simple aromatic compounds with carbon dioxide

Cobalt(III)-Catalyzed C–H Bond Amidation with Isocyanates

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