P-Stereogenic Phosphorus Ligands in Asymmetric Catalysis

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(14), P. 8657 - 8739

Published: July 2, 2024

Chiral phosphorus ligands play a crucial role in asymmetric catalysis for the efficient synthesis of useful optically active compounds. They are largely categorized into two classes: backbone chirality and P-stereogenic ligands. Most reported belong to former class. Privileged ones such as BINAP DuPhos frequently employed wide range catalytic transformations. In contrast, latter class has remained small family many years mainly because their synthetic difficulty. The late 1990s saw emergence novel with superior enantioinduction ability Rh-catalyzed hydrogenation reactions. Since then, numerous have been synthesized used This Review summarizes thus far, including stereochemical electronic properties that afford high excellent enantioselectivities. Examples reactions use this described together applications construction key intermediates natural products therapeutic agents. literature covered dates back 1968 up until December 2023, centering on studies published later years.

Language: Английский

---

Sigma-Bond Metathesis as an Unusual Asymmetric Induction Step in Rhodium-Catalyzed Enantiodivergent Synthesis of C–N Axially Chiral Biaryls

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(15), P. 8417 - 8429

Published: March 23, 2023

Mechanistic understanding of asymmetric induction plays a crucial role in designing new catalytic reactions. Reported herein is atroposelective access to C-N axially chiral isoquinolones via rhodium-catalyzed C-H activation N-alkoxy benzamides and annulation with imidoyl sulfoxonium ylides. The coupling system proceeded excellent functional group tolerance, different conditions were identified afford one or the other enantiomeric product each enantioselectivity for representative class ylide reagent, thus making both enantiomers readily available using same catalyst. Experimental computational studies revealed pathway alkylation enantio-determining formal nucleophilic substitution-C-N cyclization that mediated by rhodium catalyst σ-bond metathesis as mechanism. Computational indicated solvent-dependent enatiodivergence originated from levels neutral versus cationic species.

Language: Английский

---

Cobalt-Catalyzed Enantioselective Desymmetrization and Chemodivergent Parallel Kinetic Resolution of Unsaturated Substrates via C(sp³)–H Bond Activation

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 3860 - 3872

Published: Feb. 19, 2025

Language: Английский

---

Mechanism of a cobalt-catalyzed hydroarylation reaction and origin of stereoselectivity

Catalysis Science & Technology, Journal Year: 2022, Volume and Issue: 12(13), P. 4380 - 4387

Published: Jan. 1, 2022

In the present study, mechanism of a cobalt-catalyzed hydroarylation reaction between N -pyridylindole and 1,6-enynes origin its stereoselectivity have been systematically investigated using DFT calculation method.

Language: Английский

---

Iron/Photosensitizer-Catalyzed Directed C–H Activation Triggered by the Formation of an Iron Metallacycle

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(7), P. 4552 - 4559

Published: March 21, 2023

C–H functionalization reactions catalyzed by iron, the most abundant transition metallic element in Earth's crust, are one of ideal synthetic methods. However, there a limited number strategies for iron-catalyzed directed activation when compared to other first-row metals. Here, we report iron/photosensitizer-catalyzed alkenylation amide derivatives via σ-CAM (σ-complex-assisted metathesis) promoted situ generation an iron metallacycle. Mechanistic experiments suggest that bond cleavage would proceed from metallacycle generated rather than oxidative addition low-valent species.

Language: Английский

---

Cobalt/Organophotoredox Dual-Catalysis-Enabled Cyclization of 1,5,10-Enediynes Involving Metallole-Mediated Remote C(sp³)–H Bond Activation Leading to Axially Chiral Aryl Alkenes

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(3), P. 2049 - 2057

Published: Jan. 23, 2024

Transition-metal-catalyzed C(sp3)–H functionalization has been much less investigated compared to C(sp2)–H because the site-selectivity control in bond activation is more challenging than that activation. Site-selective without assistance of directing groups highly desirable, installation and removal are not required. Hence, cycloaddition through a site-selective C–H triggered by formation metallacycles, such as metalloles, atom- step-economical method for synthesizing complex carbo- heterocycles from simple unsaturated substrates. Herein, we report cobalt/photoredox dual-catalysis-enabled cyclization 1,5,10-enediynes via remote metallole formation, affording axially chiral aryl alkenes. Several experiments theoretical calculations suggest cleavage proceeds σ-complex-assisted metathesis (σ-CAM) intermediate.

Language: Английский

---

Harnessing Halide Ligands and External Electric Fields in Cobalt-Catalyzed Oxidative Cyclometalation: Mechanistic Insights and Reactivity Modulation

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 12, 2025

This study explores the roles of halide ligands and external electric fields (EEFs) in tuning reactivity cobalt-catalyzed oxidative cyclometalation (OCM) 1,6-enynes, focusing on concerted mechanism. Using density functional theory (DFT), we investigate how these factors influence key processes OCM step, particularly cleavage π bonds, formation M-C creation a new C-C bond. Our findings show that polar solvents lower activation barriers, while increase them, inhibiting reaction by weakening back-donation reducing orbital overlap. However, strategic application EEFs counteracts this inhibition, enhancing electron back-donation, stabilizing transition state, facilitating bond formation. The Dewar-Chatt-Duncanson (DCD) model, distortion/interaction analysis, quantum atoms molecules (QTAIM) delocalization index (DI) calculation reveal reduce cobalt center, π-back-donation raising energy barriers. work provides insights into electronic geometric can be manipulated to optimize catalytic performance synthetic transformations.

Language: Английский

---

Rhodium(I)‐Catalyzed Asymmetric Hydroarylative Cyclization of 1,6‐Diynes to Access Atropisomerically Labile Chiral Dienes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(1)

Published: Nov. 16, 2023

Abstract Axially chiral open‐chained olefins are an underexplored class of atropisomers, whose enantioselective synthesis represents a daunting challenge due to their relatively low racemization barrier. We herein report rhodium(I)‐catalyzed hydroarylative cyclization 1,6‐diynes with three distinct classes arenes, enabling highly broad range axially 1,3‐dienes that conformationally labile (Δ G ≠ ( rac )=26.6–28.0 kcal/mol). The coupling reactions in each category proceeded excellent enantioselectivity, regioselectivity, and Z/E selectivity under mild reaction conditions. Computational studies the quinoline N ‐oxide system reveal proceeds via initial oxidative 1,6‐diyne give rhodacyclic intermediate, followed by σ‐bond metathesis between arene C−H bond Rh−C(vinyl) bond, subsequent C−C reductive elimination being enantio‐determining turnover‐limiting. DFT‐established mechanism is consistent experimental studies. coupled products ‐oxides undergo facile visible light‐induced intramolecular oxygen‐atom transfer, affording epoxides complete axial‐to‐central chirality transfer.

Language: Английский

---

A computational study on cobalt-catalyzed allylic substitution of racemic allylic carbonates with amines: inner-sphere C–N reductive elimination and origins of regio- and enantioselectivities

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(12), P. 2976 - 2987

Published: Jan. 1, 2023

DFT calculations reveal an inner-sphere C–N reductive elimination pathway for the cobalt/bisoxazolinephosphine-catalyzed allylic substitution of racemic carbonates with amines.

Language: Английский

---

Rh-Catalyzed Enantioselective Hydroalkenylative Cyclization of 1,6-Enynes Constructing All-Carbon Quaternary Stereocenters

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(7), P. 4951 - 4957

Published: March 18, 2024

We report the enantioselective construction of all-carbon quaternary stereocenters (up to 99% ee) by cationic Rh(I)/Segphos-catalyzed hydroalkenylative cyclization 1,6-enynes with α-substituted acrylamides. This Rh catalysis proceeds small excesses alkenes at room temperature in most substrates yield desired products high yields and enantioselectivity. Mechanistic studies indicate acrylamide-substituted C–H bond activation processes: for acrylamides, is cleaved a Rh(III) complex (rhodacyclopentene); contrast, β-substituted Rh(I) complex.

Language: Английский

---