Light opens a new window for N-heterocyclic carbene catalysis

Chemical Science, Journal Year: 2020, Volume and Issue: 11(39), P. 10605 - 10613

Published: Jan. 1, 2020

N-Heterocyclic carbenes (NHCs) are efficient Lewis basic catalysts for the umpolung of various polarized unsaturated compounds usually including aldehydes, imines, acyl chlorides and activated esters. NHC catalysis involving electron pair transfer steps has been extensively studied; however, through single-electron (SET) processes, despite having potential to achieve chemical transformations inert bonds using green reagents, long a challenging task in organic synthesis. In parallel, visible-light-induced photocatalysis photoexcitation have established as powerful tools facilitate sustainable synthesis, they enable generation reactive radical intermediates under extremely mild conditions. Recently, number elegant visible-light-induced, NHC-catalyzed were developed accessing valuable compounds. As result, this minireview will highlight recent advances field.

Language: Английский

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Visible Light-Induced Reactions of Diazo Compounds and Their Precursors

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(11), P. 7214 - 7261

Published: May 16, 2024

In recent years, visible light-induced reactions of diazo compounds have attracted increasing attention in organic synthesis, leading to improvement existing reactions, as well the discovery unprecedented transformations. Thus, photochemical or photocatalytic generation both carbenes and radicals provide milder tools toward these key intermediates for many valuable However, vast majority transformations represent new reactivity modes compounds, which are achieved by decomposition photoredox catalysis. particular, use a redox-active photocatalysts opens avenue plethora radical reactions. The application methods led inaccessible classical associated with metal carbenes. most cases, act sources but can also serve acceptors. Importantly, described processes operate under mild, practical conditions. This Review describes this subfield compound chemistry, particularly focusing on advancements.

Language: Английский

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Visible light-mediated photolysis of organic molecules: the case study of diazo compounds

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(48), P. 7346 - 7360

Published: Jan. 1, 2023

This article discusses the photochemistry of several diazo compounds undergoing visible light-mediated photolysis to generate free carbenes (or other highly reactive intermediates), which can be sequentially trapped by different reacting partners.

Language: Английский

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Advances in heterocycle synthesis through photochemical carbene transfer reactions

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(16), P. 2125 - 2136

Published: Jan. 1, 2024

In this feature article, we focus on the photochemical strategy for construction of heterocyclic skeletons, specifically highlighting methods that employ visible light-promoted carbene transfer reactions.

Language: Английский

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Generation and Reactivity of C(1)‐Ammonium Enolates by Using Isothiourea Catalysis

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 27(5), P. 1533 - 1555

Published: June 19, 2020

C(1)-Ammonium enolates are powerful, catalytically generated synthetic intermediates applied in the enantioselective α-functionalisation of carboxylic acid derivatives. This minireview describes recent developments generation and application C(1)-ammonium from various precursors (carboxylic acids, anhydrides, acyl imidazoles, aryl esters, α-diazoketones, alkyl halides) using isothiourea Lewis base organocatalysts. Their utility intra- intermolecular C-C C-X bond forming processes on reaction with electrophiles will be showcased utilising two distinct catalyst turnover approaches.

Language: Английский

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Utilizing Vinylcyclopropane Reactivity: Palladium‐Catalyzed Asymmetric [5+2] Dipolar Cycloadditions

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(40), P. 17429 - 17434

Published: July 3, 2020

Abstract Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is great significance modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric [5+2] cycloaddition VCPs with α‐diazoketones accomplished by switching reactivity Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced good reaction efficiencies selectivities (23 examples, 52–92 % yields up 99:1 er 12.5:1 dr). In addition, computational investigations performed rationalize observed high chemo‐ periselectivities.

Language: Английский

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Access to 5,6-Spirocycles Bearing Three Contiguous Stereocenters via Pd-Catalyzed Stereoselective [4 + 2] Cycloaddition of Azadienes

Organic Letters, Journal Year: 2021, Volume and Issue: 23(8), P. 2884 - 2889

Published: March 26, 2021

We present herein a highly diastereo- and enantioselective Pd-catalyzed [4 + 2] cycloaddition of benzofuran-derived azadienes with vinyl benzoxazinanones, which represents rare stereoselective this class fused as two-atom synthon. The use phosphoramidite ligand bearing chiral secondary amine simple biphenyl backbone proved to be the key construct novel spirocyclic tetrahydroquinoline scaffold containing three contiguous stereocenters single diastereomer in high enantioselectivity.

Language: Английский

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Visible photons as ideal reagents for the activation of coloured organic compounds

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(10), P. 4926 - 4975

Published: Jan. 1, 2024

In search for the perfect wave(length). This review is dedicated to recent efforts in development of visible light driven photochemical strategies occurring coloured organic compounds.

Language: Английский

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Asymmetric Trapping of Siloxyketenes In Situ Generated from [1,3]-Silyl Migration of α-Ketoacylsilanes: A Visible-Light-Driven Palladium-Catalyzed [4 + 2] Cycloaddition

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 5796 - 5805

Published: March 25, 2025

The transition metal-catalyzed asymmetric [n + 2] cycloaddition reaction with oxy-substituted ketene intermediates remains a synthetic challenge due to the limited availability of suitable precursors. Herein, we report visible-light-driven, palladium-catalyzed [4 vinyl benzoxazinanones siloxyketene intermediates, generating structurally diverse chiral quinolinone derivatives satisfactory diastereo- and enantioselectivities. transient generation siloxyketenes from α-ketoacylsilylanes through visible-light-induced Brook rearrangement is important for success present cycloaddition. 13C-labeling experiments reveal pathway involving [1,3]-silyl migration process. side arm effects BOX ligand silyl steric hindrance α-ketoacylsilanes play crucial roles in stereoselectivity control, theoretical calculations provide insights into stereochemical outcome reaction.

Language: Английский

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Palladium-Catalyzed Diastereo- and Enantioselective [3 + 2] Cycloaddition of Vinylcyclopropanes with Azadienes: Efficient Access to Chiral Spirocycles

Organic Letters, Journal Year: 2021, Volume and Issue: 23(3), P. 826 - 831

Published: Jan. 27, 2021

Benzofuran-derived azadienes (BDAs) have been widely used as four-atom synthons in transition-metal-mediated cycloaddition reactions, while the exploitation of their reactivity a two-atom unit to construct spirocycles is still underdeveloped. Herein, we reported first palladium(0)-catalyzed diastereo- and enantioselective [3 + 2] annulation vinylcyclopropanes (VCPs) BDAs. This transformation featured with broad substrate scope (31 examples), allowing for facile access variety enantioenriched bearing quaternary stereogenic center good yields excellent regio-, diastereo-, enantioselectivities (up 93% yield, >20:1 dr, mostly >99% ee) under mild reaction conditions. Moreover, spirocyclic products could be efficiently converted structurally complex tricyclo[8.3.0.01,5]-azatridecane tricyclo[7.3.0.01,5]-azadodecane skeletons.

Language: Английский

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