NHC‐Activations on α‐, β‐, γ‐, and Beyond

The Chemical Record, Год журнала: 2023, Номер 23(7)

Опубликована: Март 14, 2023

Abstract Over the recent decades, due to special electronic characteristics and diverse reactivities, N‐heterocyclic carbene (NHC) has received significant interest in organocatalyzed reactions. The formation of Breslow intermediates by NHC can convert into acyl anion equivalent, enolates, homoenolate, azolium, vinyl enolate etc ., cycloaddition reactions these species attracted lots attention. In this review, we focus on summry development NHC‐activation carbonyl carbon (or imine carbon) situ , α‐, β‐, γ‐, beyond, reaction species.

Язык: Английский

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N‐Heterocyclic Carbene‐Catalyzed [3+3] Annulation of Alkynyl Acyl Azolium with β‐Keto Ester for the Synthesis of Tri‐Substituted α‐Pyranones

Asian Journal of Organic Chemistry, Год журнала: 2023, Номер 12(9)

Опубликована: Июль 25, 2023

Abstract The reactivity of N‐Heterocyclic carbene (NHC)‐bound alkynyl acyl azoliums is underexplored in chemistry. We herein reported an NHC‐catalyzed [3+3] annulation with β ‐keto esters. strategy features mild reaction conditions and exhibits broad substrates scope, delivering a wide range tri‐substituted α ‐pyrones moderate to excellent yields (up 95%). This approach extends the esters binucleophiles.

Язык: Английский

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A Review on Generation and Reactivity of the N-Heterocyclic Carbene-Bound Alkynyl Acyl Azolium Intermediates

Molecules, Год журнала: 2022, Номер 27(22), С. 7990 - 7990

Опубликована: Ноя. 17, 2022

N-heterocyclic carbene (NHC) has been widely used as an organocatalyst for both umpolung and non-umpolung chemistry. Previous works mainly focus on species including Breslow intermediate, azolium enolate homoenolate alkenyl acyl etc. Notably, the NHC-bound alkynyl emerged effective intermediate to access functionalized cyclic molecular skeleton until very recently. In this review, we summarized generation reactivity of intermediates, which covers efforts advances in synthesis achiral axially chiral scaffolds via intermediates. particular, mechanism related is discussed detail.

Язык: Английский

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Aerobic Oxidative N‐Heterocyclic Carbene Catalysis

The Chemical Record, Год журнала: 2023, Номер 23(7)

Опубликована: Июнь 12, 2023

Abstract The ease with which simple starting materials can be transformed into highly functionalized products has made oxidative N‐heterocyclic carbene (NHC) catalysis an area of significant interest. However, the use stoichiometric amounts high molecular weight oxidants in most reactions generates undesired equivalent amount waste. To address this issue, oxygen as terminal oxidant NHC been developed. Oxygen is attractive due to its low cost, weight, and ability generate water sole by‐product. challenging a reagent organic synthesis unreactive ground state, often requires run at temperatures results formation kinetic side‐products. This review covers development aerobic catalysis, including NHC‐catalyzed oxygen, strategies for activation, selectivity issues under conditions.

Язык: Английский

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N-heterocyclic carbene-catalyzed direct enantioselective synthesis of dihydroisoxazolo[5,4-b]pyridin-6-ones

Organic Chemistry Frontiers, Год журнала: 2023, Номер 10(4), С. 963 - 969

Опубликована: Янв. 1, 2023

A novel N-heterocyclic carbene (NHC)-catalyzed asymmetric [3 + 3] cycloaddition between α-bromoenals and 5-aminoisoxazoles has been developed.

Язык: Английский

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