Circularly Polarized Fluorescence Resonance Energy Transfer (C‐FRET) for Efficient Chirality Transmission within an Intermolecular System

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(46), P. 24549 - 24557

Published: Aug. 23, 2021

Abstract The occurrence and transmission of chirality is a fascinating characteristic nature. However, the intermolecular efficiency circularly polarized luminescence (CPL) remains challenging due to poor through‐space energy transfer. We report unique CPL from inducing achiral acceptor emit within specific liquid crystal (LC)‐based system through fluorescence resonance transfer ( C ‐FRET), wherein luminescent cholesteric LC employed as donor, rationally designed long‐wavelength aggregation‐induced emission (AIE) fluorophore acts well‐assembled acceptor. In contrast photon‐release‐and‐absorption, channel ‐FRET highly dependent upon in intrinsic chiral assembly LC, verified by deliberately separating donor keep it far beyond distance. This mode provides de novo strategy concept for high‐level information processing applications such high‐density data storage, combinatorial logic calculation, multilevel encryption decryption.

Language: Английский

---

Oxygen‐Linked Cyclopentadienyl Rhodium(III) Complexes‐Catalyzed Asymmetric C−H Arylation of Benzo[h]quinolines with 1‐Diazonaphthoquinones

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(28), P. 15510 - 15516

Published: April 16, 2021

Abstract Chiral cyclopentadienyl rhodium (CpRh) complex‐catalyzed asymmetric C−H functionalization reactions have witnessed a significant progress in organic synthesis. In sharp contrast, the reported chiral Cp ligands are limited to C‐linked and often synthetically challenging. To address these issues, we developed novel class of tunable bearing oxygen linkers, which were efficient catalysts for arylation benzo[ h ]quinolines with 1‐diazonaphthoquinones, affording axially heterobiaryls excellent yields enantioselectivity (up 99 % yield, 98.5:1.5 er). Mechanistic studies suggest that reaction is likely proceed by electrophilic activation, followed coupling cyclometalated rhodium(III) complex 1‐diazonaphthoquinones.

Language: Английский

---

Cobalt(III)/Chiral Carboxylic Acid‐Catalyzed Enantioselective Synthesis of Benzothiadiazine‐1‐oxides via C−H Activation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(28)

Published: May 2, 2022

Abstract Among sulfoximine derivatives containing a chiral sulfur center, benzothiadiazine‐1‐oxides are important for applications in medicinal chemistry. Here, we report that the combination of an achiral cobalt(III) catalyst and pseudo‐ C 2 ‐symmetric H 8 ‐binaphthyl carboxylic acid enables asymmetric synthesis from sulfoximines dioxazolones via enantioselective C−H bond cleavage. With optimized protocol, with several functional groups can be accessed high enantioselectivity.

Language: Английский

---

Rhodium‐Catalyzed Atroposelective Access to Axially Chiral Olefins via C−H Bond Activation and Directing Group Migration

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(1)

Published: Oct. 22, 2021

Axially chiral open-chain olefins represent an underexplored class of platform. In this report, two classes tetrasubstituted axially acyclic have been accessed in excellent enantioselectivity and regioselectivity via C-H activation (hetero)arenes assisted by a migratable directing group en route to coupling with sterically hindered alkynes. The indoles bearing N-aminocarbonyl afforded C-N acrylamides the assistance racemic zinc carboxylate additive. DFT studies suggest β-nitrogen elimination-reinsertion pathway for migration. Meanwhile, employment N-phenoxycarboxamide delivered C-C enamides migration oxidizing group. Experiments that both cases (hetero)arene substrate adopts well-defined orientation during activation, which turn determines disposition alkyne migratory insertion. Synthetic applications representative are demonstrated.

Language: Английский

---

Rhodium‐Catalyzed C−H Activation‐Based Construction of Axially and Centrally Chiral Indenes through Two Discrete Insertions

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(30), P. 16628 - 16633

Published: May 19, 2021

Abstract Reported herein is asymmetric [3+2] annulation of arylnitrones with different classes alkynes catalyzed by chiral rhodium(III) complexes, the nitrone acting as an electrophilic directing group. Three indenes/indenones have been effectively constructed, depending on nature substrates. The coupling system features mild reaction conditions, excellent enantioselectivity, and high atom‐economy. In particular, N ‐benzylnitrones sterically hindered afforded C−C or C−N atropochiral pentatomic biaryls a C‐centered point‐chirality in enantio‐ diastereoselectivity (45 examples, average 95.6 % ee ). These center axis are disposed distal fashion they constructed via two distinct migratory insertions that stereo‐determining under catalyst control.

Language: Английский

---

Development of Chiral Ligands for the Transition‐Metal‐Catalyzed Enantioselective Silylation and Borylation of C−H Bonds

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(9)

Published: Nov. 3, 2021

Enantioselective reactions that install functional groups at the positions of unactivated C-H bonds can be envisioned to produce intermediates for synthesis active ingredients in pharmaceuticals and agrochemicals directly from simple feedstocks. Among these bond functionalization reactions, those form carbon-silicon (C-Si) carbon-boron (C-B) have been pursued because products converted containing a wide range compounds silicon boron possess unique properties valuable medicinal materials chemistry. Although silylation borylation undergone extensive development during past two decades, enantioselective versions were not known until few years ago. In this Minireview, we present rapid bonds, with an emphasis on design types chiral ligands needed achieve intention inspire expansion transformations.

Language: Английский

---

Synthesis of Chiral Spirolactams via Sequential C−H Olefination/Asymmetric [4+1] Spirocyclization under a Simple Co^II/Chiral Spiro Phosphoric Acid Binary System

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(43), P. 23187 - 23192

Published: Aug. 26, 2021

Abstract An unprecedented enantioselective synthesis of spiro‐γ‐lactams via a sequential C−H olefination/asymmetric [4+1] spirocyclization under simple Co II /chiral spiro phosphoric acid (SPA) binary system is reported. A range biologically important are obtained with high levels enantioselectivity (up to 98 % ee ). The concise, asymmetric an aldose reductase inhibitor was successfully achieved. Notably, contrast previous reports that relied on the use cyclopentadienyl or its derivatives (achiral Cp*, Cp tBu , chiral x ) ligated III complexes requiring tedious steps prepare, cheap and commercially available cobalt(II) acetate tetrahydrate used as efficient precatalyst.

Language: Английский

---

Design and Synthesis of Tunable Chiral 2,2′‐Bipyridine Ligands: Application to the Enantioselective Nickel‐Catalyzed Reductive Arylation of Aldehydes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(20)

Published: Feb. 17, 2022

A new class of chiral 2,2'-bipyridine ligands, SBpy, featuring minimized short-range steric hindrance and structural tunability was rationally designed developed, the effectiveness demonstrated in first highly enantioselective Ni-catalyzed addition aryl halides to aldehydes. In comparison with known approaches using preformed metallic reagents, this reaction is more step-economical functional group tolerant. The mechanism a model stereocontrol were proposed based on experimental computational results.

Language: Английский

---

Rhodium(III)‐Catalyzed Asymmetric [4+1] and [5+1] Annulation of Arenes and 1,3‐Enynes: A Distinct Mechanism of Allyl Formation and Allyl Functionalization

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(50), P. 22706 - 22713

Published: Sept. 4, 2020

Abstract We report chiral Rh III cyclopentadienyl‐catalyzed enantioselective synthesis of lactams and isochromenes through oxidative [4+1] [5+1] annulation, respectively, between arenes 1,3‐enynes. The reaction proceeds a C−H activation, alkenyl‐to‐allyl rearrangement, nucleophilic cyclization cascade. mechanisms the annulations were elucidated by combination experimental computational methods. DFT studies indicated that, following activation alkyne insertion, alkenyl intermediate undergoes δ ‐hydrogen elimination allylic via six‐membered ring transition state to produce enallene hydride intermediate. Subsequent insertion allyl rearrangement affords several rhodium(III) intermediates, rare η 4 ene‐allyl species with π‐agostic interaction SN 2 ′‐type external attack nitrogen nucleophile, instead C−N reductive elimination, as stereodetermining step.

Language: Английский

---

(SCp)Rhodium‐Catalyzed Asymmetric Satoh–Miura Reaction for Building‐up Axial Chirality: Counteranion‐Directed Switching of Reaction Pathways

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(3)

Published: Nov. 16, 2022

Satoh-Miura reaction is an important method for extending π-systems by forging multi-substituted benzene rings via double aryl C-H activation and annulation with alkynes. However, the development of highly enantioselective remains rather challenging. Herein, we report asymmetric between 1-aryl benzo[h]isoquinolines internal alkynes enabled a SCpRh-catalyst. Judiciously choosing counteranion Rh-catalyst crucial desired reactivity over competitive formation azoniahelicenes. Detailed mechanistic studies support proposal counteranion-directed switching pathways in Rh-catalyzed activation.

Language: Английский

---