An overview of the applications of chiral phosphoric acid organocatalysts in enantioselective additions to CO and CN bonds

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 9(22), P. 6331 - 6399

Published: Jan. 1, 2022

Since 2004, chiral phosphoric acids (CPAs) have emerged as highyl efficient organocatalysts, providing excellent results in a wide reaction scope. In this review, the applications of CPA for enantioselective additions to CO and CN bonds are covered.

Language: Английский

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Asymmetric aza‐Friedel–Crafts Reaction of Cyclic Ketimines with 5‐Aminopyrazole Derivatives: Expedient Access to Pyrazole‐Based C2‐quaternary Indolin‐3‐Ones

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(20)

Published: Jan. 5, 2023

A chiral phosphoric acid-catalyzed enantioselective aza-Friedel-Crafts reaction of 5-aminopyrazole derivatives with cyclic ketimines attached to a neutral functional group is reported. This protocol allows the formation pyrazole-based C2-quaternary indolin-3-ones high enantioselectivities and regioselectivities. Moreover, gram-scale synthesis 5-aminopyrazole-based was performed, no decrease in yield enantioselectivity.

Language: Английский

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Copper-Catalyzed Direct Asymmetric Vinylogous Mannich Reaction between β,γ-Alkynyl-α-ketimino Esters and β,γ-Unsaturated N-Acylpyrazoles

Organic Letters, Journal Year: 2024, Volume and Issue: 26(7), P. 1376 - 1381

Published: Feb. 13, 2024

We report a Cu(I)–Ph-BPE-catalyzed asymmetric vinylogous Mannich reaction of β,γ-alkynyl-α-ketimino esters with β,γ-unsaturated N-acylpyrazoles. In this process, the Cu(I)–Ph-BPE catalyst activates ester through N,O-coordination, enabling subsequent nucleophilic addition dienolate generated from N-acylpyrazole via α-position deprotonation catalytic amount tertiary amine. The reactions gave useful products very high enantioselectivities. A broad range substrates various substituents are tolerated in reaction. versatility method was demonstrated by gram-scale reaction, and elaboration adducts also provided.

Language: Английский

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Accessing unnatural α-amino acids with tetrasubstituted stereogenic centersviacatalytic enantioselective reactions of ketimine-type α-iminoesters/α-iminoamides

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(54), P. 8343 - 8374

Published: Jan. 1, 2023

Catalytic enantioselective synthesis methodologies have been actively explored and developed owing to the significance of chiral molecules their utilities. In particular, unnatural α-amino acids with tetrasubstituted stereogenic carbon centers (α-tertiary amino acids; ATAAs) are undoubtedly among most valuable compounds. Asymmetric addition an α-iminoester or α-iminoamide is widely recognized as a straightforward, powerful, atom-economical strategy for accessing optically active derivatives. However, this type chemistry, which relies on ketimine-type electrophiles, was quite limited only few decades ago low reactivities difficulties associated enantiofacial control. This feature article comprehensively overviews research field highlights significant progress that has made. it focuses catalyst system transition state key parameters such reactions.

Language: Английский

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Regioselective [3 + 2] Annulation of β,γ-Alkynyl-α-ketimino Esters with 1,3-Dicarbonyls: The Synthesis of Highly Functionalized Dihydrofurans

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 30, 2025

A regioselective [3 + 2] annulation of β,γ-alkynyl-α-ketimino esters with 1,3-dicarbonyls is disclosed. series Z-selective dihydrofurans bearing an exocyclic double bond and a quaternary carbon center are accessed without the usage base. Control deuterium-labeling experiments have been investigated to probe into reaction mechanism. The catalyst base-free nucleophilic addition highlights transformation.

Language: Английский

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Relay Catalysis-Enabled Enantioselective Annulations of β,γ-Alkynyl-α-imino Esters with 1,3-Diones for the Divergent Synthesis of Chiral Oxacycles

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 19, 2025

A novel protocol for the chemically divergent synthesis of chiral oxacycles has been developed using organo/metal relay catalysis. The methodology integrates a stereospecific Mannich reaction between β,γ-alkynyl-α-imino esters and 1,3-diones catalyzed by bifunctional squaramide, followed Lewis acid-catalyzed regioselective annulation reactions. By switching acid employed, we achieved pathway to construct structurally related pyran furan derivatives from common intermediate. (3+3) (3+2) products were obtained in high yields excellent stereoselectivities. Comprehensive mechanistic studies conducted establish mechanism.

Language: Английский

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Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

Beilstein Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: 21, P. 533 - 540

Published: March 10, 2025

A valuable vinylogous addition reaction between 4-alkylidene-5-aminopyrazoles and alkyl trifluoropyruvates leading to highly functionalized tertiary alcohols bearing a trifluoromethyl group pyrazole ring is presented. The corresponding are obtained in moderate good yields (up 80%) high diastereoselectivity 7:1).

Language: Английский

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Emerging progress in chiral phosphoric acid-catalyzed asymmetric synthesis of unnatural α-amino acids

Catalysis Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Unnatural α-amino acids (α-UAAs) are essential components in the development of biologically active compounds, pharmaceuticals, ligands, and catalysts.

Language: Английский

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Organocatalytic regio- and enantioselective C1-arylation of β,γ-alkynyl-α-imino esters with pyrrolo[2,1-a]isoquinolines

Chemical Communications, Journal Year: 2023, Volume and Issue: 60(7), P. 831 - 834

Published: Dec. 15, 2023

We herein report regio- and enantioselective arylation of β,γ-alkynyl-α-imino esters with pyrroloisoquinolines. Using chiral phosphoric acid catalysts, a wide range novel axially tetrasubstituted α-amino allenoates were accessed in good yields excellent enantioselectivities. Notably, this transformation occurred preferentially at the sterically more hindered C1-position The potential scalability late-stage functionalization demonstrated utility current protocol.

Language: Английский

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Atroposelective Construction of Naphthylpyrazoles by Chiral Phosphoric Acid Catalyzed Enantioselective Cross‐Coupling of Pyrazoles with Naphthoquinone Esters

European Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 27(23)

Published: April 10, 2024

Abstract The catalytic asymmetric reaction of 5‐aminopyrazoles with naphthoquinone esters has been established. A wide range unprecedented axially chiral naphthylpyrazole derivatives (29 examples) have synthesized in moderate to excellent yields (up 99 % yield) enantioselectivities ee) by utilizing phosphoric acid as a catalyst. This protocol features mild conditions, broad substrate scope, good scalability and facile derivatization. Moreover, preliminary mechanistic investigation was conducted elucidate the mechanism.

Language: Английский

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