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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α-Amino Acids and Peptides as Bifunctional Reagents: Carbocarboxylation of Activated Alkenes via Recycling CO₂

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(7), P. 2812 - 2821

Published: Feb. 9, 2021

Carboxylic acids, including amino acids (AAs), have been widely used as reagents for decarboxylative couplings. In contrast to previous couplings that release CO2 a waste byproduct, herein we report novel strategy with simultaneous utilization of both the alkyl and carboxyl components from carboxylic acids. Under this unique strategy, act bifunctional in redox-neutral carbocarboxylation alkenes. Diverse, inexpensive, readily available α-AAs take part such difunctionalizations activated alkenes via visible-light photoredox catalysis, affording variety valuable but otherwise difficult access γ-aminobutyric acid derivatives (GABAs). Additionally, series dipeptides tripeptides also participate photocatalytic carbocarboxylation. Although several challenges exist system due low concentration quantitative amount CO2, well unproductive side reactions hydrodecarboxylation hydroalkylation alkenes, excellent regioselectivity moderate high chemoselectivity are achieved. This process features catalyst loading, mild reaction conditions, step atom economy, good functional group tolerance, it is scalable. The resulting products subject efficient derivations, overall amenable applications late-stage modification complex compounds. Mechanistic studies indicate carbanion generated catalytically acts key intermediate react which situ thus remains concentration. transformation represents an sustainable organic synthesis, pharmaceutics, biochemistry.

Language: Английский

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Photochemical Organocatalytic Benzylation of Allylic C–H Bonds

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(3), P. 1113 - 1118

Published: Jan. 14, 2022

We report a radical-based organocatalytic method for the direct benzylation of allylic C-H bonds. The process uses nonfunctionalized substrates and readily available benzyl radical precursors is driven by visible light. Crucial was identification dithiophosphoric acid that performs two distinct catalytic roles, sequentially acting as donor formation photoactive electron donor-acceptor (EDA) complexes then hydrogen atom abstractor. By mastering these orthogonal generation paths, organic catalyst enables benzylic radicals, respectively, to govern their selective coupling. protocol also used design three-component process, which increased synthetic potential chemistry.

Language: Английский

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Enantioselective C(sp³)–C(sp³) Reductive Cross-Electrophile Coupling of Unactivated Alkyl Halides with α-Chloroboronates via Dual Nickel/Photoredox Catalysis

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(4), P. 2081 - 2087

Published: Jan. 23, 2023

Substantial advances in enantioconvergent C(sp3)-C(sp3) bond formations have been made with nickel-catalyzed cross-coupling of racemic alkyl electrophiles organometallic reagents or nickel-hydride-catalyzed hydrocarbonation alkenes. Herein, we report an unprecedented enantioselective reductive by the direct utilization two different halides dual nickel/photoredox catalysis system. This highly selective coupling α-chloroboronates and unactivated iodides furnishes chiral secondary boronic esters, which serve as useful important intermediates realm organic synthesis enable a desirable protocol to fast construction enantioenriched complex molecules.

Language: Английский

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Sequence‐Dependent Stereodivergent Allylic Alkylation/Fluorination of Acyclic Ketones

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(5), P. 2039 - 2043

Published: Nov. 6, 2019

Abstract The stereodivergent iridium‐catalyzed allylic alkylation and fluorination of acyclic ketones is described. α‐Pyridyl‐α‐fluoroketones with vicinal tertiary quaternary stereocenters were obtained in moderate to excellent yields stereoselectivities. Distinct from known synthesis, for which two different chiral catalysts are required general, herein we report a sequence‐dependent synthesis. With only single Ir catalyst, all four possible stereoisomers the products prepared same starting materials by simply adjusting sequence asymmetric varying absolute configuration catalyst.

Language: Английский

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Utilization of C(sp³)‐Carboxylic Acids and Their Redox‐Active Esters in Decarboxylative Carbon−Carbon Bond Formation

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 363(15), P. 3693 - 3736

Published: May 11, 2021

Abstract Over the last several years, radical‐mediated decarboxylative cross‐coupling reactions employing alkyl carboxylic acids have emerged as a powerful tool for regiospecific construction of carbon−carbon bonds. Under thermal or photocatalytic conditions, wide variety C( sp 3 )‐carboxylic and their redox‐active esters undergo C−C bond formation with suitable reactant partners, leading to complex chemical scaffolds wide‐ranging applications. This synthetic strategy has advantages over more conventional organometallic reagents, including abundant starting material availability high functional group tolerance associated mild reaction conditions. review article highlights recent developments in functionalization α‐heteroatom‐substituted well challenging unactivated acids, representative examples discussed against backdrop insightful comments on mechanisms. In addition, synthesis natural products, drug molecules, late‐stage modification bioactive molecules this non‐traditional are included. been categorized into three main sections that organized around type being forged: )−C( 2 ), ). Further, separately each section. magnified image

Language: Английский

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Metal-Catalyzed Ionic Decarboxylative Cross-Coupling Reactions of C(sp³) Acids: Reaction Development, Mechanisms, and Application

ACS Catalysis, Journal Year: 2019, Volume and Issue: 10(3), P. 1742 - 1753

Published: Dec. 27, 2019

The direct transition-metal-catalyzed conversion of carboxylic acid groups into other C–C or C–X bonds provides a complementary bond disconnection to traditional cross-coupling manifolds. Decarboxylative coupling strategies can be divided two mechanistic frameworks: decarboxylative homolysis processes that generate radicals and heterolysis carbanions. challenge both inducing decarboxylation with unmodified substrates enabling efficient interception by suitable transition-metal complex has made achieving general approaches catalytic cross-couplings acids elusive. Thus, more wasteful indirect involving preactivation the unit are common. This Perspective article highlights recent work in area metal-catalyzed ionic reactions C(sp3) acids. In these processes, serves as surrogate for nucleophiles normally generated deprotonation use organometallic reagents. many cases, this approach allow alkylation under less-basic conditions, improving functional group compatibility, ease access starting materials, inhibit undesirable overfunctionalization products. Commentary on reaction development, mechanism, application is provided along comparisons related transformations.

Language: Английский

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Enantioselective Decarboxylative Hydrogen-Atom Transfer Reaction

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 6, 2025

Direct enantioselective decarboxylative transformations of carboxylic acids have become powerful tools for constructing structurally and functionally diverse molecules. Herein, an unprecedented organocatalyzed protocol enantioconvergent reduction was established by leveraging dual catalysis photoredox-mediated radical generation a thiol-catalyzed asymmetric hydrogen-atom transfer process. With this hydrodecarboxylation, variety chiral 3-substituted indolines were attained from the in moderate to excellent yields with high enantioselectivities.

Language: Английский

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Cobalt‐Catalyzed Allylic Alkylation Enabled by Organophotoredox Catalysis

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(27), P. 9199 - 9203

Published: April 18, 2019

Abstract Co‐catalyzed allylic substitution reactions have received little attention, arguably because of the lack any known advantage Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective alkylation using an in situ catalyst activation by organophotoredox This noble‐metal‐free catalytic system exhibits unprecedentedly high reactivities regioselectivities for allylation with allyl sulfone, first time, representing unique synthetic utility method compared to related Rh‐ Ir‐catalyzed reactions.

Language: Английский

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Direct Catalytic Decarboxylative Amination of Aryl Acetic Acids

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(3), P. 1313 - 1319

Published: Nov. 13, 2019

Abstract The decarboxylative coupling of a carboxylic acid with an amine nucleophile provides alternative to the substitution traditional organohalide partners. Benzoic and alkynyl acids may be directly aminated by oxidative catalysis. In contrast, methods for intermolecular alkyl conversion, including amidate rearrangements photoredox‐promoted approaches, require stoichiometric activation unit generate isocyanate or radical intermediates. Reported here is process direct chemoselective amination electron‐poor arylacetates Cu reaction proceeds at (or near) room temperature, uses native starting materials, compatible protic, electrophilic, other potentially complicating functionality. Mechanistic studies support pathway in which ionic decarboxylation generates benzylic Chan–Evans–Lam‐type process.

Language: Английский

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