Synthesis of Amines with Pendant Boronic Esters by Borrowing Hydrogen Catalysis

Winson, M. J.; James, Tony D.; Williams, Jonathan M. J.

doi:10.1021/ol402271a

Cited by 31 publications

(11 citation statements)

References 46 publications

(14 reference statements)

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“…39 With functionalized substrates such as para-and meta-boronic ester group-bearing alcohols 30 or amines 32, Ru(II)-catalyzed amine alkylation reactions were carried out to form boronic ester group-functionalized amines 31 and 33, respectively, which may be used as molecular sensors (eqn (11) and ( 12)). 40 A general and highly regioselective synthesis of pyrroles via ruthenium(II)-catalyzed three-component reaction of ketone, amine, and vicinal diol was reported (eqn ( 13)). 41 The catalyst system was composed of the commercially available [Ru( p-cymene)Cl 2 ] 2 /t-BuOK, and a variety of aryl and alkyl ketones as well as a-functionalized and activated benzylic ones were reacted with various amines (anilines, alkyl amines, and ammonia) and vicinal diols to give the corresponding heterocyclic products, pyrroles 34.…”

Section: Qingfu Wangmentioning

confidence: 99%

Substitution of alcohols by N-nucleophiles via transition metal-catalyzed dehydrogenation

2015

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Transition metal-catalyzed substitution of alcohols by N-nucleophiles (or N-alkylation of amines and related compounds with alcohols) avoids the use of alkylating agents by means of borrowing hydrogen (BH) activation of the alcohol substrates. Water is produced as the only by-product, which makes the "BH" processes atom-economic and environmentally benign. Diverse types of homogeneous organometallic and heterogeneous transition metal catalysts, and substrates such as N-nucleophiles including amines, amides, sulfonamides and ammonia, and various alcohols, can be used for this purpose, demonstrating the promising potential of "BH" processes to replace the procedures using traditional alkylating agents in pharmaceutical and chemical industries. Borrowing hydrogen activation of alcohols for C-N bond formation has recently been paid more and more attention, and a lot of new and novel procedures and examples have been documented. This critical review summarizes the recent advances in "BH" substitution of alcohols by N-nucleophiles since 2009. "Semi-BH" N-alkylation processes with or without an external hydrogen acceptor are also briefly presented. Suitable discussion of the "BH" strategy provides new principles for establishing green processes to replace the relevant traditional synthetic methods for C-N bond formation.

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Section: Qingfu Wangmentioning

confidence: 99%

Substitution of alcohols by N-nucleophiles via transition metal-catalyzed dehydrogenation

2015

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“…Following a modified reported procedure, [10a] Vilsmeier–Haack formylation at the p ‐position of N , N ′‐diphenyl‐dihydrodibenzo[ a , c ]phenazine (DPAC) followed by NaBH 4 reduction yielded key precursors 3 and 4 bi‐ and monofunctionalized, respectively. Next, the benzylic OH were reacted with 2‐( N ‐methylaminomethyl)phenylboronic acid pinacol ester in presence of [Ru( p ‐cymene)Cl 2 ]Cl 2 , DPEPhos and Na 2 CO 3 to give the corresponding tertiary amines 1 and 5 from 3 and 6 from 4 by borrowing hydrogen catalysis [12] . Boronic derivatives 1 and 2 were thus subsequently obtained in 90–94 % yields, after the removal of pinacol ester groups.…”

Section: Methodsmentioning

confidence: 99%

A Vibration‐Induced‐Emission‐Based Fluorescent Chemosensor for the Selective and Visual Recognition of Glucose

et al. 2021

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The development of chemosensors to detect analytes in biologically relevant solutions is a challenging task. We report the synthesis of a fluorescent receptor that combines vibration-induced emission (VIE) and dynamic covalent chemistry for the detection of glucose in aqueous media. We show that the bis-2-(N-methylaminomethyl)phenylboronic acid-decorated N,N'-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC) receptor 1 can detect glucose and discriminate between closely related monosaccharides including those commonly found in blood. Preliminary studies suggest monosaccharides bind to the DPAC-receptor with a 1:1 stoichiometry to produce pseudomacrocyclic complexes, which in turn leads to distinct optical changes in the fluorescent emission of the receptor for each host. Moreover, the complexationinduced change in emission can be detected visually and quantified in a ratiometric way. Our results highlight the potential of VIE-type receptors for the quantitative determination of saccharides in biological samples.

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“…Transition metal‐catalyzed N‐alkylation is an environmentally friendly method for providing primary, secondary and tertiary amines, and thus a plethora of Ru, Ir, Pd, Co, Pt, Fe and Mn complexes have been developed and used as catalysts for this reaction . Among them, inexpensive ruthenium complexes show high reactivity and are widely applied in N‐alkylation of amines with alcohols . However, a ruthenium loading of 5% or more is usually required to achieve satisfactory yields.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic investigation of imine formation in ruthenium‐catalyzed N‐alkylation of amines with alcohols

et al. 2018

Applied Organom Chemis

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Imines are observed frequently in ruthenium-catalyzed N-alkylation of amines with alcohols. Herein, nitrogen-phosphine functionalized carbene ligands were developed and used in ruthenium-catalyzed N-alkylation to explore the mechanism of imine formation. The results showed that strongly electron-donating ligands were beneficial for imine formation and alcohol dehydrogenation to generate acid. In addition, with an increase of electron density of nitrogen atom in substituted amines, the yield of imines in N-alkylation was improved. At the same time, with electron-rich imines as substrates, the transfer hydrogenation of imines became difficult. It is suggested that strongly electron-donating ligands and substrates caused an increase of electron density on the ruthenium center, which resulted in the elimination of hydrogen atoms in active species [LRuH 2 ] as hydrogen gas rather than transfer onto the imine coordinated with the ruthenium center.

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Synthesis of Amines with Pendant Boronic Esters by Borrowing Hydrogen Catalysis

Cited by 31 publications

References 46 publications

Substitution of alcohols by N-nucleophiles via transition metal-catalyzed dehydrogenation

Substitution of alcohols by N-nucleophiles via transition metal-catalyzed dehydrogenation

A Vibration‐Induced‐Emission‐Based Fluorescent Chemosensor for the Selective and Visual Recognition of Glucose

Mechanistic investigation of imine formation in ruthenium‐catalyzed N‐alkylation of amines with alcohols

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