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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Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(8), P. 4373 - 4505

Published: March 19, 2021

This Review compiles the evolution, mechanistic understanding, and more recent advances in enantioselective Pd-catalyzed allylic substitution decarboxylative oxidative substitutions. For each reaction, catalytic data, as well examples of their application to synthesis complex molecules, are collected. Sections which we discuss key aspects for high selectivity a comparison with other metals (with advantages disadvantages) also included. asymmetric substitution, data grouped according type nucleophile employed. Because prominent position use stabilized carbon nucleophiles heteronucleophiles, many chiral ligands have been developed. To better compare results, they presented by ligand types. reactions mainly promoted PHOX or Trost ligands, justifies organizing this section chronological order. results used.

Language: Английский

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Iridium-Catalyzed Asymmetric Synthesis of Functionally Rich Molecules Enabled by (Phosphoramidite,Olefin) Ligands

Accounts of Chemical Research, Journal Year: 2019, Volume and Issue: 52(9), P. 2657 - 2672

Published: June 19, 2019

ConspectusThe catalytic, asymmetric synthesis of complex molecules has been a core focus our research program for some time because developments in the area can have an immediate impact on identification novel strategies value-added molecules. In concert with this central interest, we emphasized design ligand scaffolds as tactic to discover and develop chemistry overcome well-recognized synthetic challenges. Based group's work chiral pool-derived diolefin ligands, designed implemented class hybrid (phosphoramidite,olefin) which combines properties both phosphoramidite olefin motifs impact, fine-tune, even override inherent reactivity metal center. Specifically, utilized these unique modifying ligands address several recognized limitations field iridium-catalyzed, allylic substitution. The methods documented typically employ branched, unprotected alcohols substrates obviate need rigorous exclusion air moisture.Following Takeuchi's seminal report demonstrating high aptitude Ir(I)-phosphite catalysts branch-selective substitution, concerted efforts from numerous laboratories led broadening utility reaction class. first section Account outlines process leading discovery unprecedented its validation iridium-catalyzed amination alcohols. This continues involving heteroatom-based nucleophiles within inter- intramolecular etherification, thioetherification spiroketalization processes. second highlights use readily available carbon possessing sp, sp2, sp3 hybridization series enantioselective carbon–carbon bond-forming reactions. We describe how alkylzinc, allylsilane, classes organotrifluoroborate be coupled enantioselectively enable construction key including 1,5-dienes, 1,4-dienes, 1,4-enynes. Since electronic steric renders (η3-allyl)-Ir(III) intermediate highly electrophilic, weak such alkyl olefins used. also show that more nucleophilic alkene enamines situ generated ketene acetals smoothly participate substitution reactions yield valuable piperidines γ,δ-unsaturated esters, respectively.The concept stereodivergent dual catalysis, synergistically amine catalysis iridium furnish α-allylated aldehydes containing two independently controllable stereocenters is then discussed. enabled independent, stereoselective all four possible product stereoisomers single set starting materials, was highlighted Δ9-tetrahydrocannabinol. concludes overview organometallic mechanistic studies regarding relevant intermediates catalytic cycle These allowed us better understand origin characteristics exhibited by catalyst comparison related systems.

Language: Английский

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Stereodivergent Synthesis of α,α-Disubstituted α-Amino Acids via Synergistic Cu/Ir Catalysis

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(4), P. 1508 - 1513

Published: Jan. 5, 2018

Cu/Ir dual catalysis has been developed for the stereodivergent α-allylation of aldimine esters. The method enables preparation a series nonproteinogenic α-amino acids (α-AAs) bearing two contiguous stereogenic centers in high yield with excellent stereoselectivity. All four product stereoisomers could be obtained from same set starting materials via pairwise combination chiral catalysts. Notably, one-pot protocol successfully applied bimetallic complexes to simplify manipulation catalysis. This further utilized construction key intermediate bioactive pyrrolidine derivative and concise synthesis plant growth regulator (2S,3S)-2-amino-3-cyclopropylbutanoic acid.

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 Pd/Cu Catalysis for the Dynamic Kinetic Asymmetric Transformation of Racemic Unsymmetrical 1,3-Disubstituted Allyl Acetates

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(18), P. 8097 - 8103

Published: April 19, 2020

A stereodivergent Pd/Cu catalyst system has been developed for the unprecedented dynamic kinetic asymmetric transformation (DyKAT) of racemic unsymmetrical 1,3-disubstituted allylic acetates with prochiral aldimine esters. series α,α-disubstituted α-amino acids bearing vicinal stereocenters were easily prepared excellent enantioselectivities (up to >99% ee) and diastereoselectivities >20:1 dr). Moreover, all four stereoisomers product can be readily obtained simply by switching configurations two chiral metal catalysts. Furthermore, present work highlights power synergistic catalysis consisting common bidentate ligands synthesis.

Language: Английский

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Stereodivergent Synthesis of Allenes with α,β‐Adjacent Central Chiralities Empowered by Synergistic Pd/Cu Catalysis

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(9)

Published: Jan. 3, 2023

The stereodivergent synthesis of allene compounds bearing α,β-adjacent central chiralities has been realized via the Pd/Cu-catalyzed dynamic kinetic asymmetric alkylation racemic allenylic esters. matched reactivity bimetallic catalytic system enables challenging reaction aryl-substituted acetates with sterically crowded aldimine esters smoothly under mild conditions. Various chiral non-natural amino acids a terminal allenyl group are easily synthesized in high yields and excellent diastereo- enantioselectivities (up to >20 : 1 dr, >99 % ee). Importantly, all four stereoisomers product can be readily accessed by switching configurations two metal catalysts. Furthermore, easy interconversion between uncommon η3 -butadienyl palladium intermediate featuring weak C=C/Pd coordination bond stable Csp2 -Pd is beneficial for transformation process (DyKAT).

Language: Английский

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Cobalt-Catalyzed Regio- and Enantioselective Allylic Amination

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(29), P. 11430 - 11434

Published: July 5, 2019

The first earth-abundant cobalt-catalyzed highly branched- and enantioselective allylic amination of racemic branched carbonates bearing alkyl groups with both aromatic aliphatic amines has been developed. process allows rapid access in high yields exclusively selectivity excellent enantioselectivities (normally 99% ee) under mild reaction conditions.

Language: Английский

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Synergetic iridium and amine catalysis enables asymmetric [4+2] cycloadditions of vinyl aminoalcohols with carbonyls

Nature Communications, Journal Year: 2019, Volume and Issue: 10(1)

Published: June 20, 2019

Abstract Catalytic asymmetric cycloadditions via transition-metal-containing dipolar intermediates are a powerful tool for synthesizing chiral heterocycles. However, within the field of palladium catalysis, compared with well-developed normal electron-demand electrophilic dipolarophiles, general strategy inverse ones nucleophilic dipolarophiles remains elusive, due to inherent linear selectivity in key palladium-catalyzed intermolecular allylations. Herein, based on switched regioselectivity iridium-catalyzed allylations, we achieved two [4+2] vinyl aminoalcohols aldehydes and β,γ-unsaturated ketones through synergetic iridium amine catalysis. The activation by catalysts carbonyls provide foundation subsequent resulting iridium-containing 1,4-dipoles (di)enamine dipolarophiles. former provides straightforward route diverse set enantio-enriched hydroquinolines bearing quaternary stereocenters, later represent an enantio- diastereodivergent synthesis hydroquinolines.

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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