Chiral Brønsted Acid-Catalyzed Metal-Free Asymmetric Direct Reductive Amination Using 1-Hydrosilatrane

Skrypai, Vladislav; Varjosaari, Sami E.; Azam, Fawwaz; Gilbert, Thomas M.; Adler, Marc J.

doi:10.1021/acs.joc.8b03073

Cited by 20 publications

(14 citation statements)

References 43 publications

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“…In 2019, Adler reported a substituted BINOL-derived chiral phosphoric acid catalyzed enantioselective direct reductive amination (DRA) of ketones with aryl amines using 1-hydrosilatrane as hydride source. [15] After screening a range of chiral Brønsted acids, 71 with bulky substituents on the naphthyl ring was selected to promote the DRA reaction in high conversions and good enantioselectivities (up to 84 % ee) (Scheme 31). They also proposed a plausible mechanism for the chiral Brønsted acid catalyzed DRA reaction (Figure 15).…”

Section: Chiral Brønsted Acid As Catalystmentioning

confidence: 99%

“…[14] Besides, the chiral Brønsted acid also has been found to be used as promoter in asymmetric reduction using silicon hydrides. [15] Recently, chiral quaternary ammonium salt/fluoride/hydrosilane system has also been developed, the ion-pairing catalysis has shown large potential to apply in this field. [16] In this review, we summarized the significant progress made over the last fifteen years in the field of enantioselective transformations using hydrosilanes.…”

Section: Introductionmentioning

confidence: 99%

“…However, the development of asymmetric version of Piers type reduction is still in preliminary stages [14] . Besides, the chiral Brønsted acid also has been found to be used as promoter in asymmetric reduction using silicon hydrides [15] . Recently, chiral quaternary ammonium salt/fluoride/hydrosilane system has also been developed, the ion‐pairing catalysis has shown large potential to apply in this field [16] …”

Section: Introductionmentioning

confidence: 99%

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The Development of Organocatalytic Asymmetric Reduction of Carbonyls and Imines Using Silicon Hydrides

et al. 2021

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The asymmetric reduction of prochiral ketones and ketimines represents one of the most important and practical chemical transformations toward the synthesis of valuable chiral alcohols and amines. Among the existing strategies, organocatalyzed asymmetric reduction of carbonyls and imines using silicon hydrides is attractive due to low-cost, chemical stability, and easy handling in experiments. In this review, we wish to highlight the recent progress made in the past fifteen years in this field. Four catalytic systems of different activation modes are presented and discussed in detail. We aim to help shed light on common features that enable highly enantioselective silicon hydride reductions through organocatalysis and provide the design principles for the development of more effective catalytic systems.

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Section: Chiral Brønsted Acid As Catalystmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Development of Organocatalytic Asymmetric Reduction of Carbonyls and Imines Using Silicon Hydrides

et al. 2021

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“…Using 1-hydrosilatrane (3), a novel hydrogen source was introduced for the reductive amination of ketones by Adler et al Even though high yields and up to 84 % ee could be achieved, a rather high phosphoric acid loading of 30 mol% was required. [47] The chiral ammonia borane composing of the (S)-CPA 10 and ammonia borane (2) was also successfully applied for the ATH of β-enamino esters (45 a-q) and ketimines (47 a-q) with good yields and good to excellent stereocontrol (Scheme 18). It was proven, that the phosphoric acid acts as a simple Brønsted acid to generate the reactive chiral ammonia borane.…”

Section: The Ath Of Imine Derivativesmentioning

confidence: 99%

“…Even though high yields and up to 84 % ee could be achieved, a rather high phosphoric acid loading of 30 mol% was required. [47] …”

Section: Reduction Of C=n Double Bondsmentioning

confidence: 99%

Chiral Phosphoric Acids as Versatile Tools for Organocatalytic Asymmetric Transfer Hydrogenations

et al. 2021

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Herein, recent developments in the field of organocatalytic asymmetric transfer hydrogenation (ATH) of C=N, C=O and C=C double bonds using chiral phosphoric acid catalysis are reviewed. This still rapidly growing area of asymmetric catalysis relies on metal-free catalysts in combination with biomimetic hydrogen sources. Chiral phosphoric acids have proven to be extremely versatile tools in this area, providing highly active and enantioselective alternatives for the asymmetric reduction of α,β-unsaturated carbonyl compounds, imines and various heterocycles. Eventually, such transformations are more and more often used in multicomponent/cascade reactions, which undoubtedly shows their great synthetic potential and the bright future of organocatalytic asymmetric transfer hydrogenations.

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Additive‐Free Transfer Hydrogenative Direct Asymmetric Reductive Amination Using a Chiral Pyridine‐Derived Half‐Sandwich Catalyst

Gao,

Wang,

Zhang

et al. 2023

Angewandte Chemie

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Chiral amines are broadly used compounds in pharmaceutical industry and organic synthesis, and reductive amination reactions have been the most appreciated methods for their syntheses. However, one‐step transfer hydrogenative direct asymmetric reductive amination (THDARA) that could expand the scope, simplify the operation and eliminate the use of additives has been challenging. In this work, based on the Xiao's racemic transfer hydrogenative reductive amination in 2010 and our recent work in novel chiral pyridine ligands, chiral half‐sandwich iridium catalysts were rationally designed and synthesized. Using the optimized catalyst and azeotropic mixture of formic acid and triethylamine as the hydrogen source, a broad range of α‐chiral (hetero)aryl amines, including various polar functional groups and heterocycles, were prepared in generally high yield and enantioselectivity under mild and operationally simple conditions. Density functional theory (DFT) calculation of the catalytically active Ir−H species and the key hydride transfer step supported the chiral pyridine‐induced stereospecific generation of the iridium center, and the enantioselection by taming the highly flexible key transition structure with multiple attractive non‐covalent interactions. This work introduced a type of effective chiral catalysts for simplified approach to medicinally important chiral amines, as well as a rare example of robust enantioselective transition‐metal catalysis.

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Chiral Brønsted Acid-Catalyzed Metal-Free Asymmetric Direct Reductive Amination Using 1-Hydrosilatrane

Cited by 20 publications

References 43 publications

The Development of Organocatalytic Asymmetric Reduction of Carbonyls and Imines Using Silicon Hydrides

The Development of Organocatalytic Asymmetric Reduction of Carbonyls and Imines Using Silicon Hydrides

Chiral Phosphoric Acids as Versatile Tools for Organocatalytic Asymmetric Transfer Hydrogenations

Additive‐Free Transfer Hydrogenative Direct Asymmetric Reductive Amination Using a Chiral Pyridine‐Derived Half‐Sandwich Catalyst

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