Three-Component, Interrupted Radical Heck/Allylic Substitution Cascade Involving Unactivated Alkyl Bromides

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(22), P. 10173 - 10183

Published: May 7, 2020

Developing efficient and selective strategies to approach complex architectures containing (multi)stereogenic centers has been a long-standing synthetic challenge in both academia industry. Catalytic cascade reactions represent powerful means of rapidly leveraging molecular complexity from simple feedstocks. Unfortunately, carrying out Heck-type involving unactivated (tertiary) alkyl halides remains an unmet owing unavoidable β-hydride elimination. Herein, we show that modular, practical, general palladium-catalyzed, radical three-component coupling can indeed overcome the aforementioned limitations through interrupted Heck/allylic substitution sequence mediated by visible light. Selective 1,4-difunctionalization 1,3-dienes, such as butadiene, achieved employing different commercially available nitrogen-, oxygen-, sulfur-, or carbon-based nucleophiles bromides (>130 examples, mostly >95:5 E/Z, >20:1 rr). Sequential C(sp3)–C(sp3) C–X (N, O, S) bonds have constructed efficiently with broad scope high functional group tolerance. The flexibility versatility strategy illustrated gram-scale reaction streamlined syntheses ether, sulfone, tertiary amine products, some which would be difficult access via currently established methods.

Language: Английский

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Stereodivergent Construction of Tertiary Fluorides in Vicinal Stereogenic Pairs by Allylic Substitution with Iridium and Copper Catalysts

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(33), P. 13066 - 13073

Published: July 25, 2019

Although much effort has been spent on the enantioselective synthesis of tertiary alkyl fluorides, compounds containing such a stereogenic center within an array stereocenters, particularly two vicinal ones, remains synthetic challenge, and no method to control configuration each independently reported. We describe strategy achieve stereodivergent centers, one fluorine atom, by forming connecting carbon-carbon bond with catalyst system comprising iridium complex that controls at electrophilic carbon copper nucleophilic fluorine-containing carbon. These reactions occur alkyl- aryl-substituted allylic esters unstabilized enolates azaaryl ketones, esters, amides in high yield, diastereoselectivity, enantioselectivity (generally >90% >20:1 dr, 97-99% ee). Access all four stereoisomers products demonstrates precise configurations independently. This methodology extends construction quaternary stereocenters similarly yield selectivity. DFT calculations uncover origin stereoselectivity enolate substitution.

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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Catalytic Enantio- and Regioselective Addition of Nucleophiles in the Intermolecular Hydrofunctionalization of 1,3-Dienes

ACS Catalysis, Journal Year: 2019, Volume and Issue: 10(2), P. 1060 - 1076

Published: Dec. 12, 2019

Catalytic enantioselective synthesis of small-molecule building blocks with allylic stereogenic centers is an important objective in organic synthesis, but preparing this motif wherein the adjacent olefin 1,2-disubstituted a single step tremendous challenge. Late-transition-metal-catalyzed intermolecular couplings nucleophiles and 1,3-dienes hydrofunctionalization reactions have quickly emerged as compelling approach to these related compounds. In Perspective, we illustrate how diene hydrofunctionalizations provided avenue complex, highly desirable chemical space that not readily accessed by other technologies. We also aim provide some insight into varying mechanistic pathways nuances myriad help inform future reaction catalyst design.

Language: Английский

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Catalytic radical generation of π-allylpalladium complexes

Nature Catalysis, Journal Year: 2020, Volume and Issue: 3(4), P. 393 - 400

Published: March 23, 2020

Language: Английский

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Recent Developments in Enantioselective Transition Metal Catalysis Featuring Attractive Noncovalent Interactions between Ligand and Substrate

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(18), P. 10672 - 10714

Published: Aug. 14, 2020

Enantioselective transition metal catalysis is an area very much at the forefront of contemporary synthetic research. The development processes that enable efficient synthesis enantiopure compounds unquestionable importance to chemists working within many diverse fields central science. Traditional approaches solving this challenge have typically relied on leveraging repulsive steric interactions between chiral ligands and substrates in order raise energy one diastereomeric states over other. By contrast, Review examines alternative tactic which a set attractive noncovalent operating are used control enantioselectivity. Examples where creative approach has been successfully applied render fundamental enantioselective presented discussed. In cases examined, ligand scaffold carefully designed accommodate these interactions, while others, critical was only elucidated subsequent computational mechanistic studies. Through exploration discussion recent reports encompassing wide range reaction classes, we hope inspire continue develop asymmetric transformations based powerful concept.

Language: Английский

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Iridium-catalyzed Z -retentive asymmetric allylic substitution reactions

Science, Journal Year: 2021, Volume and Issue: 371(6527), P. 380 - 386

Published: Jan. 21, 2021

Keeping Z -olefins intact with iridium Transition metal catalysis offers a versatile means of modifying carbon centers adjacent to carbon-carbon double bonds. However, in the course these reactions, bond tends get weakened, allowing its substituents swivel back and forth. Thus, if two large groups start out on same side axis (a geometry known as -olefin), they end up opposite sides product. Jiang et al. report chiral catalyst that prevents this swiveling just long enough substitute enantioselectively (see Perspective by Malcolmson). Science , issue p. 380 ; see also 345

Language: Английский

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The Merger of Photoredox and Cobalt Catalysis

Trends in Chemistry, Journal Year: 2020, Volume and Issue: 2(5), P. 410 - 426

Published: Feb. 13, 2020

Language: Английский

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Bimetallic Catalysis in Stereodivergent Synthesis

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(45)

Published: Aug. 2, 2022

Abstract Bimetallic catalysis has emerged as an efficient strategy for the development of new chemical reactions. Importantly, this also provides a simple and powerful platform stereodivergent synthesis, whereby all possible stereoisomers products bearing two stereocenters can be easily prepared from same set starting materials. In Minireview, allylic substitution, propargylic hydrofunctionalization, annulation based on bimetallic been summarized. It is expected that more catalytic systems will developed applied synthesis valuable molecules.

Language: Английский

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Enantio‐ and Diastereodivergent Synthesis of Spirocycles through Dual‐Metal‐Catalyzed [3+2] Annulation of 2‐Vinyloxiranes with Nucleophilic Dipoles

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(47), P. 24941 - 24949

Published: Sept. 17, 2021

The development of efficient and straightforward methods for obtaining all optically active isomers structurally rigid spirocycles from readily available starting materials is great value in drug discovery chiral ligand development. However, the stereodivergent synthesis bearing multiple stereocenters remains an unsolved challenge owing to steric hindrance ring strain. Herein, we report enantio- diastereodivergent through dual-metal-catalyzed [3+2] annulation oxy π-allyl metallic dipoles with less commonly employed nucleophilic (imino esters). A series spiro compounds a pyrroline olefin were easily synthesized manner (up 19:1 dr, >99 % ee), which showed promise as new type N-olefin ligand. Preliminary mechanistic studies also carried out understand process this bimetallic catalysis.

Language: Английский

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