Iridium-Catalyzed Asymmetric Allylic Substitution Reactions

Chemical Reviews, Journal Year: 2018, Volume and Issue: 119(3), P. 1855 - 1969

Published: Dec. 24, 2018

In this review, we summarize the origin and advancements of iridium-catalyzed asymmetric allylic substitution reactions during past two decades. Since first report in 1997, Ir-catalyzed have attracted intense attention due to their exceptionally high regio- enantioselectivities. been significantly developed recent years many respects, including ligand development, mechanistic understanding, substrate scope, application synthesis complex functional molecules. an explicit outline ligands, mechanism, scope nucleophiles, applications is presented.

Language: Английский

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Catalytic Asymmetric Dearomatization by Transition-Metal Catalysis: A Method for Transformations of Aromatic Compounds

Chem, Journal Year: 2016, Volume and Issue: 1(6), P. 830 - 857

Published: Dec. 1, 2016

Language: Английский

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Advances in Catalytic Asymmetric Dearomatization

ACS Central Science, Journal Year: 2021, Volume and Issue: 7(3), P. 432 - 444

Published: Feb. 22, 2021

Asymmetric catalysis has been recognized as the most enabling strategy for accessing chiral molecules in enantioenriched forms. Catalytic asymmetric dearomatization is an emerging and dynamic research subject catalysis, which received considerable attention recent years. The direct transformations from readily available aromatic feedstocks to structurally diverse three-dimensional polycyclic make catalytic reactions of broad interest both organic synthesis medicinal chemistry. However, inherent difficulty disruption aromaticity demands a large energy input during process, might be incompatible with conditions generally required by catalysis. In this Outlook, we will discuss representative strategies examples various compounds try convince readers that overcoming above obstacles, could advance chemical sciences many respects.

Language: Английский

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Stereodivergent Allylic Substitutions with Aryl Acetic Acid Esters by Synergistic Iridium and Lewis Base Catalysis

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 139(1), P. 87 - 90

Published: Dec. 17, 2016

The preparation of all possible stereoisomers a given chiral molecule bearing multiple stereocenters by simple and unified method is significant challenge in asymmetric catalysis. We report stereodivergent allylic substitutions with aryl acetic acid esters catalyzed synergistically metallacyclic iridium complex benzotetramisole. Through permutations the enantiomers two catalysts, four products adjacent are accessible high diastereoselectivity enantioselectivity. resulting activated ester can be converted readily to enantioenriched amides, unactivated esters, carboxylic acids one-pot manner.

Language: Английский

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Catalytic Enantioselective Construction of Spiro Quaternary Carbon Stereocenters

ACS Catalysis, Journal Year: 2019, Volume and Issue: 9(3), P. 1820 - 1882

Published: Jan. 31, 2019

The catalytic enantioselective assembly of spirocyclic molecules featuring a spiro quaternary carbon stereocenter is currently great interest because such privileged 3D structures are widely present in natural products that exhibit broad spectrum biological and pharmacological activities. This review summarizes the advances based on six major synthetic strategies showcases reaction mechanisms detail. advantages limitations each strategy presented, remaining opportunities outlined.

Language: Английский

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Spiroindoles as Intermediates/Products in Transition Metal-Catalyzed Dearomatization of Indoles

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(14), P. 9442 - 9475

Published: July 3, 2023

Spirocyclic indole derivatives are fascinating tridimensional molecular scaffolds from both a synthetic and biological point of view. Among the many strategies developed to access these structures, transition metal catalysis has recently led impressive advances, especially relying on unique reactivity dearomatized spirocyclic intermediates. These species can indeed evolve toward or nonspirocyclic products through rearomatization-driven processes, which at same time highly challenging control but also source large structural diversity. This review highlights most prominent methods past decade that involve spirocyclization tethered functional group may be activated by metal, leading rearomatized products. The discussion is particularly focused spiroindoleninium intermediate complex mechanistic features regarding its evolution, dependent catalytic systems.

Language: Английский

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Exploring the Chemistry of Spiroindolenines by Mechanistically-Driven Reaction Development: Asymmetric Pictet–Spengler-type Reactions and Beyond

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(4), P. 974 - 987

Published: April 10, 2020

ConspectusThe Pictet–Spengler reaction is a fundamental named in organic chemistry, and it the most straightforward method for synthesis of tetrahydro-β-carbolines, core structure embedded numerous alkaloids. Spiroindolenines are often proposed as possible intermediates reactions. However, whether spiroindolenine species an intermediate mechanism asymmetric remains unclear. Questions about role regarding include following: Can be formed effectively under conditions? If so, what its fate? Is delivery enantioenriched tetrahydro-β-carboline product related to intermediate? Previous studies these questions have not reached consensus. Therefore, elucidating will advance field synthetic chemistry.The first highly enantioselective spiroindolenines that same molecular scaffold key was accomplished by Ir-catalyzed intramolecular allylic substitution indol-3-yl carbonate. In this reaction, piperidine, pyrrolidine, or cyclopentane ring can introduced conjunction with indolenine structure.Spiroindolenines were found undergo ring-expansive migration reactions when treated catalytic amount acid, leading tetrahydro-β-carbolines tetrahydrocarbazoles. Comprehensive DFT calculations Born–Oppenheimer dynamics simulations provided insight into process. It has been stereochemistry strongly correlated electronic properties migratory group along acidity catalyst. Close interactions between positively charged electron-rich indole favor stereospecificity migration. Furthermore, continuous mechanistic spectrum obtained on basis two readily accessible energetic parameters derived from computed energies competing transition states relative species. This theoretical model provides unified understanding which further supported rationally designed prototype Chemically stereochemically controllable achieved multiple potential groups available.The reactivity also explored beyond A one-pot dearomatization/stereoconvergent allows facile racemic starting materials. An unprecedented six- seven-membered vinyliminium moiety involved reactive group. facilitates stereoselective thermodynamically challenging indole-annulated rings. process interrupted. The electrophilic released retro-Mannich captured inter- nucleophile, thus providing new entries structurally diverse polycyclic derivatives.Therefore, probed manipulating turn, insights gained herein aid chemical transformations toward various target molecules. study serves vivid example positive interplay experimental investigations chemistry.

Language: Английский

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Iridium‐Catalyzed Asymmetric Allylic Dearomatization by a Desymmetrization Strategy

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(47), P. 15093 - 15097

Published: Oct. 5, 2017

Abstract A desymmetrization strategy was developed involving iridium‐catalyzed allylic dearomatization of indoles. The six‐membered‐ring spiroindolenines contain three contiguous stereogenic centers, including an all‐carbon quaternary center, and were obtained in up to 99 % yield with ee >95:5 d.r. When treated a catalytic amount tosylic acid, six‐membered spiroindolenine undergoes unprecedented six‐to‐seven‐membered ring expansion, affording the corresponding hexahydroazepino[4,5‐ b ]indole.

Language: Английский

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Asymmetric Dearomatization of Indole by Palladium/PC‐Phos‐Catalyzed Dynamic Kinetic Transformation

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(49), P. 21991 - 21996

Published: Sept. 2, 2020

Abstract A palladium‐catalyzed intermolecular dynamic kinetic asymmetric dearomatization of 3‐arylindoles with internal alkynes was developed the use achiral Xantphos and chiral sulfinamide phosphine ligand ( PC‐Phos ) as co‐ligands. This method could deliver various spiro[indene‐1,3′‐indole] compounds in good yields (up to 95 % yield) up 98 ee . The salient features transformation include readily available substrates, ease scale‐up versatile functionalization products. mechanistic experiments gave some insights on active intermediates.

Language: Английский

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Diastereocontrolled Construction of Spiroindolenines via Hexafluoroisopropanol-Promoted Dearomative Epoxide–Indole Cyclization

Organic Letters, Journal Year: 2024, Volume and Issue: 26(5), P. 1088 - 1093

Published: Jan. 25, 2024

Herein, we report the discovery of ipso-selective, dearomatizing spirocyclization indole-tethered epoxides as a fundamentally new approach for constructing spiroindolenines equipped with three contiguous stereogenic centers under complete diastereocontrol (dr >99:1) and in high yields. Promoted by hexafluoroisopropanol, protocol features broad substrate scope, easy scale-up, versatile transformations synthesized spiroindolenines.

Language: Английский

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