A Carbene Relay Strategy for Cascade Insertion Reactions DOI
Li Li,

Chenggang Mi,

Guanwang Huang

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(45)

Published: Sept. 19, 2023

Abstract Insertion reactions that involve stabilized electrophilic metallocarbenes are of great importance for installing α‐heteroatoms to carbonyl compounds. Nevertheless, the limited availability carbene precursors restricts introduction only a single heteroatom. In this report, we describe new approach based on an I (III) /S (VI) reagent promotes cascade insertion heteroatoms. This is achieved by sequentially generating two α‐heteroatom‐substituted metal carbenes in one reaction. We found mixed ylide reacts efficiently with transition catalyst and X−H bond (where X=O, N). transformation leads sequential formation sulfoxonium‐ X‐substituted Rh‐carbenes, enabling further another Y−H bond. Remarkably, wide range symmetrical unsymmetrical α,α‐ O , ‐, N ‐subsituted ketones can be prepared under mild ambient conditions. addition, successfully demonstrated other cascades, such as CN/CN double amidation, C−H/C−S insertion, C−S/Y−H Y=S, N, O, C). Notably, latter cascades enabled simultaneous installation three functional groups α‐carbon compounds step. These demonstrate versatility our approach, allowing synthesis esters multiple using common precursor.

Language: Английский

Diastereoselective Transfer of Tri(di)fluoroacetylsilanes‐Derived Carbenes to Alkenes DOI
Yizhi Zhang, Gang Zhou,

Xingxing Gong

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(25)

Published: April 13, 2022

Stereoselective cyclopropanation reaction of alkenes is usually achieved by metal complexes via singlet-metal-carbene intermediates. However, previous transition-metal-catalyzed with acylsilanes afforded low diastereoselectivity. Herein, we report the first visible-light-induced transition-metal-free terminal trifluoroacetylsilanes and difluoroacetylsilanes. Both aromatic aliphatic as well electron-deficient are suitable substrates for highly cis-selective [2+1] cyclization reaction. A combination experimental computational studies identified triplet carbenes being key intermediates in this transformation. The gram scale late-stage functionalization demonstrated synthetic potential strategy.

Language: Английский

Citations

70
Electron‐Rich Oxycarbenes: New Synthetic and Catalytic Applications beyond Group 6 Fischer Carbene Complexes DOI Open Access
Gang Zhou,

Zhuanzhuan Guo,

Xiao Shen

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(13)

Published: Jan. 3, 2023

Abstract Oxycarbenes have emerged as useful intermediates in synthetic chemistry. Compared to the widely studied oxycarbene metal complexes bearing Group 6 metals, and catalytic applications of oxycarbenes beyond Fischer carbene are less explored because difficulty controlling their reactivity need use a stoichiometric amount presynthesized complex starting material. This Minireview summarizes early late‐transition‐metal highlights recent advances free reactions transition‐metal‐catalyzed involving oxycarbenes. We hope this will inspire further developments emerging area.

Language: Английский

Citations

44
Catalytic synthesis of β-lactam derivatives by carbonylative cycloaddition of acylsilanes with imines via a palladium Fischer-carbene intermediate DOI Creative Commons

Tetsuya Inagaki,

Takuya Kodama, Mamoru Tobisu

et al.

Nature Catalysis, Journal Year: 2024, Volume and Issue: 7(2), P. 132 - 138

Published: Jan. 15, 2024

Abstract Fischer-type carbene complexes are characterized by the presence of a π -donating group, such as an alkoxy group on carbon. Despite notable progress that has been made in synthetic methods involve use complexes, stoichiometric amounts still required for reactions and catalytic variants remain elusive. This limitation primarily stems from lack suitable precursors, which is sharp contrast to fact bearing electron-withdrawing can be readily generated corresponding diazo esters. Here we report acylsilanes function precursor Fischer-carbene complex action palladium catalyst. system used carbonylative cycloaddition with imines form densely substituted β-lactam derivatives. A key siloxycarbene–palladium intermediate was isolated successfully X-ray crystallography.

Language: Английский

Citations

16
Radical Brook rearrangement: past, present, and future DOI
Yunxiao Zhang, Gang Zhou, Shanshan Liu

et al.

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

This review aims to provide an overview of radical Brook rearrangement, which is organized by grouping three type reactive species generated via the unique rearrangement process.

Language: Английский

Citations

2
Intramolecular photochemical [2 + 1]-cycloadditions of nucleophilic siloxy carbenes DOI Creative Commons

Amanda Bunyamin,

Carol Hua, Anastasios Polyzos

et al.

Chemical Science, Journal Year: 2022, Volume and Issue: 13(11), P. 3273 - 3280

Published: Jan. 1, 2022

Visible light induced singlet nucleophilic carbenes undergo rapid [2 + 1]-cycloaddition with tethered olefins to afford unique bicyclo[3.1.0]hexane and bicyclo[4.1.0]heptane scaffolds. This cyclopropanation process requires only visible irradiation proceed, circumventing the use of exogenous (photo)catalysts, sensitisers or additives showcases a vastly underexplored mode reactivity for in chemical synthesis. The discovery additional transformations including cyclopropanation/retro-Michael/Michael cascade chromanones photochemical C-H insertion reaction are also described.

Language: Английский

Citations

49
Visible Light‐Mediated Cyclopropanation: Recent Progress DOI

Ze‐Le Chen,

Yang Xie, Jun Xuan

et al.

European Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 2022(44)

Published: Oct. 21, 2022

Abstract Cyclopropanes are one of the most important strained rings existing in various pharmaceutical products and secondary metabolites. They also widely used total synthesis natural products, medicinal chemistry, materials science. In past years, photochemical cyclopropanation has been gradually developed as a robust attractive synthetic method to prepare diverse cyclopropane backbones. this review, we summarize recent advances visible light‐mediated synthesis, especially using carbene transfer strategy photocatalytic radical reactions.

Language: Английский

Citations

39
Recent progress and perspectives in photo-induced organic reactions of acylsilanes DOI

Wan Pyo Hong,

Hee Nam Lim, Inji Shin

et al.

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(3), P. 819 - 836

Published: Jan. 1, 2023

This review provides recent advances and insights into photoirradiation reactions of acylsilanes, notably via key nucleophilic siloxycarbene intermediates. Nucleophilic addition, insertion reaction, cyclization are discussed in terms reaction mechanism scope.

Language: Английский

Citations

38
Visible-Light-Mediated Energy Transfer Enables Cyclopropanes Bearing Contiguous All-Carbon Quaternary Centers DOI

Dingding Xia,

Rong-Kai Wu, Jinxin Wang

et al.

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(14), P. 9806 - 9816

Published: July 11, 2023

Cyclopropanes bearing contiguous all-carbon quaternary centers continue to attract attention due their bioactivities. However, methods obtain cyclopropanes with remain largely unexplored the high steric hindrance of these compounds. Herein, we report a visible-light-mediated energy-transfer (EnT) strategy realize in situ donor/donor carbenes from readily available N-tosylhydrazones, facilitating synthesis highly congested EWG-free cyclopropanes. Through this approach, are rapidly installed into complex bioactive molecules, fluorescent and other useful building blocks that challenging synthesize. Detailed mechanistic reactions DFT studies clearly demonstrated role photosensitizer, formation carbenes, necessity light base system.

Language: Английский

Citations

34
Photocatalyzed Borylcyclopropanation of Alkenes with a (Diborylmethyl)iodide Reagent DOI Creative Commons
Jiefeng Hu, Man Tang, Jing Wang

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(38)

Published: Aug. 2, 2023

Cyclopropane skeletons play a prominent role in the development of organic synthesis and pharmaceutical chemistry. Herein, we report design stable, multifunctional (diborylmethyl)iodide reagent (CHI(Bpin)2 ) for photoinduced cyclopropanation alkenes, providing an array 1,2-substituted cyclopropylboronates good yields. This α-haloboronic ester can be readily synthesized on multigram scale from commercially available starting materials. Furthermore, protocol displays high chemo- diastereoselectivity, excellent functional-group tolerance, allows late-stage borylcyclopropanation complex molecules. Mechanistic studies reveal that proceeds through radical addition/polar cyclization pathway mediated by photocatalyst fac-Ir(ppy)3 visible light.

Language: Английский

Citations

34
Photosensitized O 2 enables intermolecular alkene cyclopropanation by active methylene compounds DOI
Dhruba P. Poudel, Amrit Pokhrel, Raj Kumar Tak

et al.

Science, Journal Year: 2023, Volume and Issue: 381(6657), P. 545 - 553

Published: Aug. 3, 2023

Cyclopropanes are key features in many preclinical, clinical, and commercial drugs, as well natural products. The most prolific technique for their synthesis is the metal-catalyzed reaction of an alkene with a diazoalkane, highly energetic reagent requiring stringent safety precautions. Discovery alternative innocuous reagents remains ongoing challenge. Herein, we report simple photoredox-catalyzed intermolecular cyclopropanation unactivated alkenes active methylene compounds. proceeds neutral solvent under air or dioxygen (O 2 ) photoredox catalyst excited by blue light-emitting diode light iodine co-catalyst that either added molecular generated situ from alkyl iodides. Mechanistic investigations indicate photosensitized O plays vital role generation carbon-centered radicals both addition compounds to ring closure.

Language: Английский

Citations

33