Catalytic Enantioselective 6π Photocyclization of Acrylanilides DOI Creative Commons

Benjamin A. Jones,

Pearse Solon, Mihai V. Popescu

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(1), P. 171 - 178

Published: Dec. 26, 2022

Controlling absolute stereochemistry in catalytic photochemical reactions is generally challenging owing to high rates of background reactivity. Successful strategies broadly rely on selective excitation the reaction substrate when associated with a chiral catalyst. Recent studies have demonstrated that Lewis acid complexes can enable energy transfer from photosensitizer facilitate enantioselective triplet state reactions. Here, we apply this approach catalysis 6π photocyclization through design an iridium optimized undergo only presence complex. Among group iridium(III) sensitizers, enantioselectivity and yield closely correlate photocatalyst within narrow window enabled by modest reduction upon binding scandium/ligand These results demonstrate tuning offers means suppress reactivity improve

Language: Английский

Enantioselective Formal Vinylogous N–H Insertion of Secondary Aliphatic Amines Catalyzed by a High-Spin Cobalt(II) Complex DOI
Wei Yang, Maoping Pu, Xiaobin Lin

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(25), P. 9648 - 9656

Published: June 21, 2021

Vinylcarbene insertion into the nitrogen–hydrogen (N–H) bond of amines allows direct access to α,β-unsaturated γ-amino acid derivatives, meeting a marked challenge in control regio- and enantioselectivities. Here, we report highly γ-selective enantioselective N–H bonds aliphatic or aromatic secondary with vinyl substituted α-diazo pyrazoleamides using high-spin chiral N,N′-dioxide/cobalt(II) complex catalyst. The method affords wide variety valuable optically active Z- E-type amides. Calculation reveals spin state change from quartet cobalt(II) doublet Co(II)-carbene species for facile Z-selective nucleophilic addition.

Language: Английский

Citations

56
Enantioselective Radical Addition to Ketones through Lewis Acid-Enabled Photoredox Catalysis DOI
Liuzhen Hou, Yuqiao Zhou, Yu Han

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(48), P. 22140 - 22149

Published: Nov. 22, 2022

Photocatalysis opens up a new window for carbonyl chemistry. Despite multitude of photochemical reactions compounds, visible light-induced catalytic asymmetric transformations remain elusive and pose formidable challenge. Accordingly, the development simple, efficient, economic systems is ideal pursuit chemists. Herein, we report an enantioselective radical photoaddition to ketones through Lewis acid-enabled photoredox catalysis wherein in situ formed chiral N,N'-dioxide/Sc(III)-ketone complex serves as temporary photocatalyst trigger single-electron transfer oxidation silanes generation nucleophilic species, including primary, secondary, tertiary alkyl radicals, giving various enantioenriched aza-heterocycle-based alcohols good excellent yields enantioselectivities. The results electron paramagnetic resonance (EPR) high-resolution mass spectrum (HRMS) measurements provided favorable evidence stereocontrolled addition process involved this reaction.

Language: Английский

Citations

52
Photoinduced Chemo‐, Site‐ and Stereoselective α‐C(sp3)−H Functionalization of Sulfides DOI
Zhenda Tan,

Shibo Zhu,

Yangbin Liu

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(29)

Published: April 21, 2022

Abstract The ubiquity of sulfur‐containing molecules in biologically active natural products and pharmaceuticals has long attracted synthetic chemists to develop efficient strategies towards their synthesis. strategy direct α‐C(sp 3 )−H modification sulfides provides a streamlining access complex molecules. Herein, we report photoinduced chemo‐, site‐ stereoselective functionalization using isatins as the photoredox reagent coupling partner catalyzed by chiral gallium(III)‐ N,N ′‐dioxide complex. reaction proceeds through verified single‐electron transfer (SET) mechanism with high efficiency, excellent functional group tolerance, well broad substrate scope. Importantly, this cross‐coupling protocol is highly selective for late‐stage methionine‐related peptides, regardless inherent structural similarity complexity diverse residues.

Language: Английский

Citations

46
Feng chiralN,N′-dioxide ligands: uniqueness and impacts DOI
Dian‐Feng Chen, Liu‐Zhu Gong

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(14), P. 3676 - 3683

Published: Jan. 1, 2023

Privileged Feng ligands feature designer N , ’-dioxide amides with a unique conformational and coordination flexibility. This highlight summarizes the increasingly profound impact of on modern catalytic asymmetric synthesis.

Language: Английский

Citations

41
Asymmetric Epoxidation of Alkenes Catalyzed by a Cobalt Complex DOI
Qianwen He, Maoping Pu, Zheng Jiang

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(28), P. 15611 - 15618

Published: July 5, 2023

Asymmetric epoxidation of alkenes catalyzed by nonheme chiral Mn–O and Fe–O catalysts has been well established, but Co–O for the purpose remain virtually undeveloped due to oxo wall. Herein is first reported a cobalt complex realize enantioselective cyclic acyclic trisubstituted using PhIO as oxidant in acetone, wherein tetra-oxygen-based N,N′-dioxide with sterically hindered amide subunits plays crucial role supporting formation intermediate electrophilic oxygen transfer. Mechanistic studies, including HRMS measurements, UV–vis absorption spectroscopy, magnetic susceptibility, DFT calculations, were carried out, confirming species quartet Co(III)-oxyl tautomer. The mechanism origin enantioselectivity also elucidated based on control experiments, nonlinear effects, kinetic calculations.

Language: Английский

Citations

25
Iron-Catalyzed Asymmetric Imidation of Sulfides via Sterically Biased Nitrene Transfer DOI
Zhenzhong Liu, Hongli Wu,

H Huiqi Zhang

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(26), P. 18050 - 18060

Published: June 15, 2024

Transition-metal-catalyzed enantioselective nitrene transfer to sulfides has emerged as one of the most powerful strategies for rapid construction enantioenriched sulfimides. However, achieving stereocontrol over highly active earth-abundant transition-metal nitrenoid intermediates remains a formidable challenge compared with precious metals. Herein, we disclose chiral iron(II)/N,N′-dioxide-catalyzed imidation dialkyl and alkyl aryl using iminoiodinanes precursors. A series sulfimides were obtained in moderate-to-good yields high enantioselectivities (56 examples, up 99% yield, 98:2 e.r.). The utility this methodology was demonstrated by late-stage modification complex molecules synthesis insecticide sulfoxaflor related bioactive compounds. Based on experimental studies theoretical calculations, water-bonded high-spin iron species identified key intermediate. observed stereoselectivity original from steric repulsion between amide unit ligand cave bulky substituent sulfides. Additionally, dioxazolones proved be suitable acylnitrene precursors presence an iron(III)/N,N′-dioxide complex, resulting formation enantioselectivity-reversed (14 81% 97:3

Language: Английский

Citations

11
Catalytic Asymmetric Dearomative [2 + 2] Photocycloaddition/Ring-Expansion Sequence of Indoles with Diversified Alkenes DOI
Liuzhen Hou, Longqing Yang,

Gaofei Yang

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(33), P. 23457 - 23466

Published: July 12, 2024

Developing novel strategies for catalytic asymmetric dearomatization (CADA) reactions is highly valuable. Visible light-mediated photocatalysis demonstrated to be a powerful tool activate aromatic compounds further synthetic transformations. Herein, dearomative [2 + 2] photocycloaddition/ring-expansion sequence of indoles with simple alkenes was reported, providing facile access enantioenriched cyclopenta[

Language: Английский

Citations

11
IronIII-catalyzed asymmetric inverse-electron-demand hetero-Diels–Alder reaction of dioxopyrrolidines with simple olefins DOI Creative Commons

Tangyu Zhan,

Liang Zhou, Yuqiao Zhou

et al.

Chemical Science, Journal Year: 2024, Volume and Issue: 15(13), P. 4797 - 4803

Published: Jan. 1, 2024

A highly enantioselective [4 + 2] cycloaddition of a number simple olefins with cyclic hetero-diene dioxopyrrolidines is realized by chiral iron( iii )/ N , ′-dioxide complex catalyst.

Language: Английский

Citations

10
Design of rigid chiral bipyridine-2NO tetradentate ligands: application in asymmetric catalysis DOI
Yuheng Wang, Pan Hu, Xirui Wang

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(5), P. 1314 - 1321

Published: Jan. 1, 2024

A new class of chiral bipyridine-2NO ligands, which incorporate the advantages both bipyridine skeleton and pyrroloimidazolone-based N -oxide moiety, was developed.

Language: Английский

Citations

9
Bimetallic Palladium/Cobalt Catalysis for Enantioselective Allylic C−H Alkylation via a Transient Chiral Nucleophile Strategy DOI

Hongkai Wang,

Yang Xu, Fangqing Zhang

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(12)

Published: Jan. 18, 2022

Abstract An asymmetric allylic C−H functionalization has been developed by making use of transient chiral nucleophiles, as well bimetallic synergistic catalysis with an achiral Pd 0 catalyst and a N,N′‐dioxide‐Co II complex. A variety β‐ketoesters N‐Boc oxindoles coupled allylbenzenes aliphatic terminal alkenes were tolerated, furnishing the desired alkylation products in high yields (up to 99 %) excellent regioselectivities enantioselectivities % ee) .

Language: Английский

Citations

36