Highly Efficient Oxidative Amidation of Aldehydes with Amine Hydrochloride Salts

Yoo, Woo‐Jin; Li, Chao‐Jun

doi:10.1021/ja064315b

Cited by 429 publications

(147 citation statements)

References 22 publications

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“…[99] Similar to the ruthenium-promoted reaction disclosed by Milstein and co-workers, the copper-catalyzed process traverses a hemiaminal intermediate (Scheme 54). The competing amine oxidation has been circumvented by protonation of the nitrogen atom as an HCl salt.…”

Section: Metal-based Redox Processesmentioning

confidence: 75%

Chemoselectivity and the Curious Reactivity Preferences of Functional Groups

2009

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Achieving high levels of chemoselectivity has been the Achilles' heel of chemical synthesis. The excitement generated by the successful realization of chemoselective strategies underscores the painstaking efforts to define a set of conditions conducive to selection among the available reaction pathways. We discuss in this Review various aspects of chemoselectivity that have been addressed in a range of synthetic methods over the past decade. We have focused on the proposed mechanistic basis of the reactions under consideration in an attempt to categorize them and highlight the key concepts that have been emerging on the basis of these studies. Our overview of recent advances in chemoselective processes suggests that significant progress has been made, but a lot of challenges lie ahead.

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Section: Metal-based Redox Processesmentioning

confidence: 75%

Chemoselectivity and the Curious Reactivity Preferences of Functional Groups

2009

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“…Secondary amides [1] also serve as powerful directing groups in CÀH activation. [2] Ketones are also a class of extremely versatile molecules that enable a number of fundamental transformations in organic synthesis.…”

mentioning

confidence: 99%

Versatile and Direct Transformation of Secondary Amides into Ketones by Deaminative Alkylation with Organocerium Reagents

et al. 2012

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“…The direct amidation of aldehydes with amines is the most desired approach to amides because it is economical and starting materials are readily available. Various efficient catalysts have been explored for this process [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]; however, some of these systems require the use of peroxide [2,3], heating, or equivalent alkali metal amides [5]. Since the first example of amidation of aldehydes with amines catalyzed by homoleptic lanthanide amides was reported [17], various lanthanide complexes, such as tris-guanidinate lanthanide complexes [18], bis-amidinate lanthanide complexes [19] and anionic lanthanide aryloxides [20], have been shown to behave as efficient catalysts under mild conditions.…”

mentioning

confidence: 99%

Heterobimetallic clusters of Na8Ln(OtBu)10(OH) as homogeneous catalysts for amidation of aldehydes with amines

Cai

et al. 2010

Chin. Sci. Bull.

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Heterobimetallic clusters of Na 8 Ln(O t Bu) 10 (OH) (Ln = ytterbium, europium, samarium and neodymium) are found to be useful catalysts for amidation of aldehydes with amines under mild conditions. The catalytic activity depends on the central metal ion in the cluster, and the order activity is ytterbium < europium < samarium ≈ neodymium. The catalysts show a wide range of scope in their activity towards amines including aliphatic amines and secondary cyclic amines such as pyrrolidine and piperidine. heterobimetallic clusters, amidation, aldehyde, amine Citation: Cai C Y, Li L, Xu F, et al. Heterobimetallic clusters of Na 8 Ln(O t Bu) 10 (OH) as homogeneous catalysts for amidation of aldehydes with amines. Because the amide group is an essential motif in natural products, pharmaceuticals and polymers [1], the formation of amides is one of the most important reactions in organic synthesis. The direct amidation of aldehydes with amines is the most desired approach to amides because it is economical and starting materials are readily available. Various efficient catalysts have been explored for this process [2-16]; however, some of these systems require the use of peroxide [2,3], heating, or equivalent alkali metal amides [5]. Since the first example of amidation of aldehydes with amines catalyzed by homoleptic lanthanide amides was reported [17], various lanthanide complexes, such as tris-guanidinate lanthanide complexes [18], bis-amidinate lanthanide complexes [19] and anionic lanthanide aryloxides [20], have been shown to behave as efficient catalysts under mild conditions. We recently found that heterobimetallic clusters Na 8 Ln(O t Bu) 10 (OH) (Ln = Nd, Sm, Eu and Yb) can be synthesized easily in high yield and showed extremely high activity for polymerization of lactones [21]. The results *Corresponding authors (promoted us to explore the applications of these clusters in organic synthesis. In this report, the high activity of heterobimetallic lanthanide clusters for catalyzing the amidation of aldehydes with amines under mild conditions is presented.The heterobimetallic clusters Na 8 Ln(O t Bu) 10 (OH)(Ln = Nd, Sm, Eu and Yb) were synthesized in accordance with a literature method [21]. The catalytic activity of these clusters for the reaction of benzaldehyde 1a with pyrrolidine 2a was first tested at 25°C using a catalyst loading of 1 mol% based on the lanthanide metal. As shown in Table 1, all of the clusters behaved as catalysts for this transformation, yielding the target product 3aa in moderate to excellent yield depending on the cluster used. Increasing the molar ratio of 1a to 2a increased the reaction yield (Table 1, entries 1-3). An excess of aldehyde (3 equiv.) is required for obtaining a high yield of the product. This is because the aldehyde also acts as an oxidant and the Tishchenko reaction competes with the amidation [22,23]. The lanthanide metals influence the activity with the order Yb < Eu < Sm ≈ Nd. The strong Lewis acidity of ytterbium may be the reason

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Highly Efficient Oxidative Amidation of Aldehydes with Amine Hydrochloride Salts

Abstract: A mild and efficient copper-catalyzed oxidative amidation of aldehydes was developed using amine HCl salts and tert-butyl hydroperoxide as an oxidant.

Cited by 429 publications

References 22 publications

Chemoselectivity and the Curious Reactivity Preferences of Functional Groups

Chemoselectivity and the Curious Reactivity Preferences of Functional Groups

Versatile and Direct Transformation of Secondary Amides into Ketones by Deaminative Alkylation with Organocerium Reagents

Heterobimetallic clusters of Na8Ln(OtBu)10(OH) as homogeneous catalysts for amidation of aldehydes with amines

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