Chemistry of α‐Aminoboronic Acids and their Derivatives

Dembitsky, Valery M.; Srebnik, Morris

doi:10.1002/9783527631780.ch4

Cited by 6 publications

(5 citation statements)

References 121 publications

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“…The amine–boranes (R 1 x NH (3‑ x ) BH (3‑ y ) R 2 y , where x , y ≤ 3) are well-known as hydroborating agents and selective reducing agents (for example, chiral amine–borane complexes can be used in enantioselective syntheses). − These compounds find many interesting applications − and are considered as prospective materials for reversible hydrogen storage systems due to their high H 2 volumetric and gravimetric density. − Amine–boranes and related bifunctional compounds (metal borohydride ammonia borane complexes, metal tetrahydroborate ammoniates, − metal amidoborane borohydrides, , amidoborane ammoniates, metal hydrazine–boranes, , etc.) containing both acidic and basic groups are of particular interest for these purposes, as these compounds are capable to evolve hydrogen at heating .…”

Section: Introductionmentioning

confidence: 99%

Dihydrogen Bond Intermediated Alcoholysis of Dimethylamine–Borane in Nonaqueous Media

et al. 2015

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Dimethylamine-borane (DMAB) acid/base properties, its dihydrogen-bonded (DHB) complexes and proton transfer reaction in nonaqueous media were investigated both experimentally (IR, UV/vis, NMR, and X-ray) and theoretically (DFT, NBO, QTAIM, and NCI). The effects of DMAB concentration, solvents polarity and temperature on the degree of DMAB self-association are shown and the enthalpy of association is determined experimentally for the first time (-ΔH°assoc = 1.5-2.3 kcal/mol). The first case of "improper" (blue-shifting) NH···F hydrogen bonds was observed in fluorobenzene and perfluorobenzene solutions. It was shown that hydrogen-bonded complexes are the intermediates of proton transfer from alcohols and phenols to DMAB. The reaction mechanism was examined computationally taking into account the coordinating properties of the reaction media. The values of the rate constants of proton transfer from HFIP to DMAB in acetone were determined experimentally [(7.9 ± 0.1) × 10(-4) to (1.6 ± 0.1) × 10(-3) mol(-1)·s(-1)] at 270-310 K. Computed activation barrier of this reaction ΔG(‡theor)298 K(acetone) = 23.8 kcal/mol is in good agreement with the experimental value of the activation free energy ΔG(‡exp)270 K = 21.1 kcal/mol.

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Section: Introductionmentioning

confidence: 99%

Dihydrogen Bond Intermediated Alcoholysis of Dimethylamine–Borane in Nonaqueous Media

et al. 2015

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“…This paves the way for study of such molecules as analogs of amino acids where the unusual, electron-donating NHC-boryl group replaces the usual, electron-withdrawing amino group. Many boron analogs of amino acids exist, but typically the boron functionality replaces either the carboxy carbon or the α-carbon of the amino acid …”

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confidence: 99%

N-Heterocyclic Carbene Boryl Iodides Catalyze Insertion Reactions of N-Heterocyclic Carbene Boranes and Diazoesters

et al. 2017

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Boron-hydrogen bond insertion reactions of N-heterocyclic carbene (NHC) boranes and diazoesters can be catalyzed by NHC-boryl iodides and produce stable α-NHC-boryl esters. The conditions of the reaction resemble the previous rhodium-catalyzed transformations (only the catalyst is different); however, the mechanisms of the two reactions are probably very different. The new boryl iodide catalyzed method is adept at producing α-substituted-α-NHC-boryl esters, and this has led to a family of NHC-boryl esters with amino acid and amino-acid-like side chains.

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“…45 However, examples of hydrolytically stable amide chelated boranes have been largely unexplored. Given the increasing interest in α-borylamides 46 we attempted to convert the borane 14b into a boronate ester. Amidoborane 14b was easily converted to the catechol ester 15 by heating in the presence of excess catechol in toluene (Figure 7).…”

Section: Hydroboration Of Tetrasubstituted En-amidementioning

confidence: 99%

Isomerization of N-Allyl Amides To Form Geometrically Defined Di-, Tri-, and Tetrasubstituted Enamides

2017

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Enamides represent bioactive pharmacophores in various natural products, and have become increasingly common reagents for asymmetric incorporation of nitrogen functionality. Yet the synthesis of the requisite geometrically defined enamides remains problematic, especially for highly substituted and Z-enamides. Herein we wish to report a general atom economic method for the isomerization of a broad range of N-allyl amides to form Z-di-, tri-, and tetrasubstituted enamides with exceptional geometric selectivity. This report represents the first examples of a catalytic isomerization of N-allyl amides to form non-propenyl disubstituted, tri- and tetrasubstituted enamides with excellent geometric control. Applications of these geometrically defined enamides towards the synthesis of cis vicinal amino alcohols and tetrasubstituted α-borylamido complexes are discussed.

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Chemistry of α‐Aminoboronic Acids and their Derivatives

Cited by 6 publications

References 121 publications

Dihydrogen Bond Intermediated Alcoholysis of Dimethylamine–Borane in Nonaqueous Media

Dihydrogen Bond Intermediated Alcoholysis of Dimethylamine–Borane in Nonaqueous Media

N-Heterocyclic Carbene Boryl Iodides Catalyze Insertion Reactions of N-Heterocyclic Carbene Boranes and Diazoesters

Isomerization of N-Allyl Amides To Form Geometrically Defined Di-, Tri-, and Tetrasubstituted Enamides

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