Molecular Co-Catalyst Confined within a Metallacage for Enhanced Photocatalytic CO₂ Reduction

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(3), P. 2275 - 2285

Published: Jan. 12, 2024

The construction of structurally well-defined supramolecular hosts to accommodate catalytically active species within a cavity is promising way address catalyst deactivation. resulting catalysts can significantly improve the utilization catalytic sites, thereby achieving highly efficient chemical conversion. In this study, Co-metalated phthalocyanine (

Language: Английский

---

Enantioselective Synthesis of Axially Chiral Alkylidenecycloalkanes via Copper-Catalyzed Functionalization of Acyl Allenols

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 2351 - 2358

Published: Jan. 24, 2025

Language: Английский

---

Amino Acid-Derived Ionic Chiral Catalysts Enable Desymmetrizing Cross-Coupling to Remote Acyclic Quaternary Stereocenters

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(30), P. 16796 - 16811

Published: July 20, 2023

Synthetic application of asymmetric catalysis relies on strategic alignment bond construction to creation chirality a target molecule. Remote desymmetrization offers distinctive advantages spatial decoupling catalytic transformation and generation stereogenic element. However, such separation presents substantial difficulties for the chiral catalyst discriminate distant enantiotopic sites through reaction three or more bonds away from prochirality center. Here, we report strategy that establishes acyclic quaternary carbon stereocenters cross-coupling reactions at distal positions aryl substituents. The new class amino acid-derived ionic catalysts enables desymmetrizing (enantiotopic-group-selective) Suzuki-Miyaura reaction, Sonogashira Buchwald-Hartwig amination between diverse diarylmethane scaffolds aryl, alkynyl, coupling partners, providing rapid access enantioenriched molecules project substituents widely spaced in three-dimensional space. Experimental computational investigations reveal electrostatic steering substrates by C-terminus ligands interactions. Cooperative ion-dipole interactions catalyst's amide group potassium cation aid preorganization transmits asymmetry product. This study demonstrates it is practical achieve precise long-range stereocontrol engineering arrangements catalysts' substrate-recognizing groups metal centers.

Language: Английский

---

Chemo-, regio- and enantioselective hydroformylation of trisubstituted cyclopropenes: access to chiral quaternary cyclopropanes

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: July 29, 2024

Catalytic asymmetric synthesis of polysubstituted chiral cyclopropane presents a significant challenge in organic due to the difficulty enantioselective control. Here we report rhodium-catalyzed highly chemo-, regio- and hydroformylation trisubstituted cyclopropenes affording quaternary cyclopropanes. Importantly, easy made sterically bulky ligand L1 can effectively suppress hydrogenation decomposition reactions give cyclopropanes with high enantioselectivities for both aryl alkyl functionalized substrates. Control experiments computational studies reveal hindered well-defined pocket instead substrates bearing electron-withdrawing diester groups is important controlling enantioselectivity regioselectivity. Scale-up reaction follow-up diverse transformations are also presented. Density Functional theory (DFT) computations suggest that enantio-selectivities originate from cyclopropene insertion Rh-H bond. The regioselectivity found benefit presence more efficient noncovalent interactions (NCIs) manifesting form C–H···Cl, C–H···N, l.p(Cl)···π contacts. Transition-metal-catalyzed represents an atom-economic clean approach preparation aldehydes efficiency. Herein, authors

Language: Английский

---

Combinatorial Ligand Assisted Simultaneous Control of Axial and Central Chirality in Highly Stereoselective C−H Allylation

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(2)

Published: Nov. 24, 2023

The significance of stereoselective C-H bond functionalization thrives on its direct application potential to pharmaceuticals or complex chiral molecule synthesis. Complication arises when there are multiple stereogenic elements such as a center and an axis chirality control. Over the years cooperative assistance ligands has been applied control only centers. In this work, we harness essence ligand approach two different in same by atroposelective allylation synthesize axially biaryls from racemic precursor. crucial roles played phosphoric acid amino concert helped us obtain one major stereoisomer out four distinct possibilities.

Language: Английский

---

Bifunctional Chiral Electrocatalysts Enable Enantioselective α‐Alkylation of Aldehydes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 22, 2024

Herein, we describe an innovative approach to the asymmetric electrochemical α-alkylation of aldehydes facilitated by a newly designed bifunctional chiral electrocatalyst. The highly efficient electrocatalyst combines aminocatalyst with redox mediator. It plays dual role as mediator for electrooxidation, while simultaneously providing remarkable induction stereoselective aldehydes. Additionally, this novel catalyst exhibits enhanced catalytic activity and excellent control comparable conventional systems. As result, strategy provides new avenue versatile electrochemistry. electrooxidation diverse phenols enables C-H/C-H oxidative in chemo- fashion. Detailed mechanistic studies experiments cyclic voltammetry analysis demonstrate possible reaction pathways origin enantio-induction.

Language: Английский

---

Cyclodextrin-assisted fluorescein decoration of gold nanoclusters for ratiometric and selective Hg2+ analysis

Frontiers in Analytical Science, Journal Year: 2025, Volume and Issue: 4

Published: Jan. 22, 2025

Introduction The construction of nanomaterial-based ratiometric detection systems usually requires covalent modification, which undergoes reactive environments and may change the natural properties supporting nanomaterials. Methods In this study, dualemissive fluorescein-decorated gold nanoclusters (F-Au NCs) through cyclodextrin-supported host–guest interaction (non-covalent modification) are explored as Hg 2+ nanoprobes d 10 –d -interactioncaused fluorescence quenching Au NCs. Results Discussion fluorescein decoration only provides a fluorescent internal reference but does not -Au NCs affinity nature. Ratiometric selective is achieved proposed F-Au NC probes with limit 15 nM. analysis in river water samples small relative standard deviations validates practical application these probes.

Language: Английский

---

Formally Stereoretentive S_N1 Reactions of Homoallylic Tertiary Alcohols Via Nonclassical Carbocation

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

Published: May 27, 2025

We present a stereoretentive nucleophilic substitution of homoallylic tertiary alcohols via the formation nonclassical cyclopropyl carbinyl (CPC) carbocation intermediate. This strategy enables creation highly congested centers with preserved stereocontrol, addressing typical challenges instability and reactivity in SN1 mechanisms. The stabilization CPC intermediate is crucial for achieving precise regio- stereoselectivity, significantly enhancing utility SN1-type mechanisms complex molecule synthesis.

Language: Английский

---

Iridium-Catalyzed Nitrene-Mediated Enantioselective 1,2-Hydride Shift Enabled by Attractive Noncovalent Interactions for Chiral δ-Lactam Synthesis

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

Published: June 3, 2025

In modern organic chemistry, 1,2-hydride shifts of carbocations are generally considered to be highly rapid processes, typically exhibiting activation barriers ∼2-4 kcal/mol─significantly faster than conventional SN1 or E1 reactions. Consequently, achieving a catalytic enantioselective shift remains significant challenge. Herein, we introduce nitrene-mediated strategy that generates carbocation intermediates through intramolecular metal-nitrenoid transfer alkenes, followed by ligand-enabled, stereocontrolled, and accelerated facilitated attractive noncovalent interactions. This methodology yields δ-lactams bearing contiguous γ,δ-stereocenters with excellent yields, diastereoselectivities, enantioselectivities (most examples >95% ee, >20:1 dr). The versatility this rearrangement platform is demonstrated its mild reaction conditions wide substrate scope, accommodating diverse nucleophiles, including carbon, oxygen, nitrogen-based species, as well biologically relevant molecules. Mechanistic investigations revealed the serves stereodetermining step, driven Complementary computational studies further enhanced C-H···π interactions play critical role increasing interaction energy, which directs pathway ensures high stereoselectivity.

Language: Английский

---

A Synergistic Bimetallic Ti/Co-Catalyzed Isomerization of Epoxides to Allylic Alcohols Enabled by Two-State Reactivity

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(14), P. 6285 - 6295

Published: March 22, 2024

Isomerization of epoxides into versatile allylic alcohols is an atom-economical synthetic method to afford vicinal bifunctional groups. Comprehensive density functional theory (DFT) calculations were carried out elucidate the complex mechanism a bimetallic Ti/Co-catalyzed selective isomerization allyl by examining several possible pathways. Our results suggest involving (1) radical-type epoxide ring opening catalyzed Cp2Ti(III)Cl leading Ti(IV)-bound β-alkyl radical, (2) hydrogen-atom transfer (HAT) Co(II) catalyst form Ti(IV)-enolate and Co(III)–H intermediate, (3) protonation give alcohols, (4) proton abstraction Co(I) species followed electron regenerate active Ti(III) species. Moreover, catalysis two-state reactivity enable key rate-determining HAT step. Furthermore, subtle balance between dispersion-driven processes entropy-driven monometallic determines most favorable pathway, among which process energetically more in all steps except vital study should provide in-depth mechanistic understanding catalysis.

Language: Английский

---