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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Ir/Cu Dual Catalysis: Enantio- and Diastereodivergent Access to α,α-Disubstituted α-Amino Acids Bearing Vicinal Stereocenters

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(6), P. 2080 - 2084

Published: Jan. 30, 2018

We describe a fully stereodivergent synthesis of range α,α-disubstituted α-amino acids via an Ir/Cu-catalyzed α-allylation readily available imine esters. The introduction Cu-Phox complex-activated ester into the chiral iridium-catalyzed allylic allylation process is crucial for its high reactivity and excellent enantio- diastereoselectivity (up to >99% ee >20:1 dr). Importantly, two catalysts allow full control over configuration stereocenters, affording all stereoisomers desired products. utility this methodology was demonstrated by synthesizing dipeptides analogues bioactive molecules in manner.

Language: Английский

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Stereodivergent Allylation of Azaaryl Acetamides and Acetates by Synergistic Iridium and Copper Catalysis

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(4), P. 1239 - 1242

Published: Jan. 10, 2018

We report stereodivergent allylic substitution reactions of esters with prochiral enolates derived from azaaryl acetamides and acetates to form products addition the at most substituted carbon an allyl moiety two catalysts, a chiral metallacyclic iridium complex bisphosphine-ligated copper(I) complex, which individually control configuration electrophilic nucleophilic atoms, respectively. By simple permutations enantiomers all four stereoisomers containing stereogenic centers were synthesized high diastereoselectivity enantioselectivity. A variety bearing pyridyl, benzothiazolyl, benzoxazolyl, pyrazinyl, quinolinyl isoquinolinyl moieties found be suitable for this transformation.

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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Generation and Application of (Diborylmethyl)zinc(II) Species: Access to Enantioenriched gem‐Diborylalkanes by an Asymmetric Allylic Substitution

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(39), P. 12930 - 12934

Published: July 2, 2018

We report the successful generation of (diborylmethyl)zinc(II) species by transmetallation beteween isolable (diborylmethyl)lithium and zinc(II) halide (X=Br, Cl) their application in synthesis enantioenriched gem-diborylalkanes bearing a stereogenic center at β-position diboryl groups an asymmetric allylic substitution reaction. The reaction has broad substrate scope, various can be obtained good yields with excellent enantioselectivity. Further elaboration provides access to diverse set valuable chiral building blocks.

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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Ni-Catalyzed Regiodivergent and Stereoselective Hydroalkylation of Acyclic Branched Dienes with Unstabilized C(sp³) Nucleophiles

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(38), P. 16486 - 16492

Published: Sept. 1, 2020

Two complementary regiodivergent [(P,N)Ni]-catalyzed hydroalkylations of branched dienes are reported. When amides employed as unstabilized C(sp3) nucleophiles, a highly regioselective 1,4-addition process is favored. The addition products obtained in high yield and with excellent stereocontrol the internal olefin. With use chiral ligand imides carbon 3,4-addition protocol was developed, enabling construction two contiguous tertiary stereocenters single step moderate to levels diastereocontrol enantiocontrol. Both methods operate under mild reaction conditions, display broad scope, show functional group tolerance. synthetic potential 3,4-hydroalkylation established via series postcatalytic modifications.

Language: Английский

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Iridium-Catalyzed Aerobic α,β-Dehydrogenation of γ,δ-Unsaturated Amides and Acids: Activation of Both α- and β-C–H bonds through an Allyl–Iridium Intermediate

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 140(2), P. 735 - 740

Published: Dec. 18, 2017

Direct aerobic α,β-dehydrogenation of γ,δ-unsaturated amides and acids using a simple iridium/copper relay catalysis system is described. We developed new strategy that overcomes the challenging issue associated with low α-acidity acids. Instead α-C–H metalation, this reaction proceeds by β-C–H activation, which results in enhanced α-acidity. Conjugated dienamides dienoic were synthesized excellent yield reaction, uses protocol. Mechanistic experiments suggest catalyst resting state mechanism both cleavage accelerated.

Language: Английский

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Iridium-Catalyzed Intramolecular Asymmetric Allylic Alkylation of Hydroxyquinolines: Simultaneous Weakening of the Aromaticity of Two Consecutive Aromatic Rings

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(8), P. 3114 - 3119

Published: Feb. 12, 2018

Intramolecular asymmetric allylic alkylation reactions of 5- and 7-hydroxyquinoline derivatives were realized by a chiral Ir/NHC catalyst. A series functionalized cyclic enones afforded in excellent yields (up to 99%) high enantioselectivity 97% ee). Theoretical computations revealed that the aromaticity two consecutive rings hydroxyquinoline substrates is significantly weakened. highly efficient formal synthesis (-)-gephyrotoxin was accomplished based on this method.

Language: Английский

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Palladium‐Catalyzed Asymmetric C(sp³)−H Allylation of 2‐Alkylpyridines

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(30), P. 9465 - 9469

Published: June 4, 2018

Abstract The palladium‐catalyzed asymmetric side‐chain C(α)‐allylation of 2‐alkylpyridines, without using an external base, was developed. high linear selectivities and enantioselectivities were achieved new chiral diamidophosphite monodentate ligands. Given that the reaction conditions do not require this catalyst system enabled chemoselective 2‐alkylpyridines containing α‐carbonyl C−H bonds, which are more acidic than α‐pyridyl bonds.

Language: Английский

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