Diboron(4)‐Catalyzed Remote [3+2] Cycloaddition of Cyclopropanes via Dearomative/Rearomative Radical Transmission through Pyridine

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(52)

Published: Nov. 8, 2022

Abstract Ring structures such as pyridine, cyclopentane or their combinations are important motifs in bioactive molecules. In contrast to previous cycloaddition reactions that necessitated a directly bonded initiating functional group, this work demonstrated novel through‐(hetero)arene radical transmission concept for selective activation of remote bond. An efficient, metal‐free and atom‐economical [3+2] between 4‐pyridinyl cyclopropanes alkenes alkynes has been developed modular synthesis pyridine‐substituted cyclopentanes, cyclopentenes bicyclo[2.1.1]hexanes difficult access using known methods. This complexity‐building reaction was catalyzed by very simple inexpensive diboron(4) compound took place via dearomative/rearomative processes. The substrate scope broad more than 100 new compounds were prepared generally high yields. Mechanistic experiments density function theory (DFT) investigation supported relay catalytic cycle involving alkylidene dihydropyridine intermediates boronyl transfer.

Language: Английский

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Access to 5,6-Spirocycles Bearing Three Contiguous Stereocenters via Pd-Catalyzed Stereoselective [4 + 2] Cycloaddition of Azadienes

Organic Letters, Journal Year: 2021, Volume and Issue: 23(8), P. 2884 - 2889

Published: March 26, 2021

We present herein a highly diastereo- and enantioselective Pd-catalyzed [4 + 2] cycloaddition of benzofuran-derived azadienes with vinyl benzoxazinanones, which represents rare stereoselective this class fused as two-atom synthon. The use phosphoramidite ligand bearing chiral secondary amine simple biphenyl backbone proved to be the key construct novel spirocyclic tetrahydroquinoline scaffold containing three contiguous stereocenters single diastereomer in high enantioselectivity.

Language: Английский

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Ligand-Controlled, Palladium-Catalyzed Asymmetric [4+4] and [2+4] Cycloadditions

Organic Letters, Journal Year: 2021, Volume and Issue: 23(6), P. 2292 - 2297

Published: March 8, 2021

Ligand-controlled, palladium-catalyzed asymmetric [4+4] and [2+4] cycloaddition reactions of benzofuran-derived azadienes have been developed. Taking advantage chiral P,N-ligand (S,Rp)-PPFA, we obtained a variety benzofuro[2,3-c][1,5] oxazocines in good yields with excellent enantioselectivities via reactions. Employing P,P-ligand (S)-Cl-MeO-BIPHEP, the chemo- regioselectivities were switched to synthesize tetrahydropyran-fused spirocyclic compounds efficiency

Language: Английский

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Recent advances in Pd-catalyzed asymmetric cyclization reactions

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 53(2), P. 883 - 971

Published: Dec. 18, 2023

This review aims to collect advancements in enantioselective palladium-catalyzed cyclization reactions over the past eleven years, and it is organized into thirteen sections depending on different types of transformations involved.

Language: Английский

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Access to spiro-bicyclo[2.1.1]hexanes via BF₃·Et₂O-catalyzed formal [2π + 2σ] cycloaddition of bicyclo[1.1.0]butanes with benzofuran-derived oxa(aza)dienes

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(16), P. 4539 - 4545

Published: Jan. 1, 2024

Rapid access to diverse spiro[benzofuran-2,2′-bicyclo[2.1.1]hexanes] via BF 3 ·Et 2 O-catalyzed [2π + 2σ] cycloaddition of bicyclo[1.1.0]butanes with readily available benzofuran-derived oxa(aza)dienes.

Language: Английский

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Expanding Stereoelectronic Limits of endo-tet Cyclizations: Synthesis of Benz[b]azepines from Donor–Acceptor Cyclopropanes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(34), P. 13952 - 13961

Published: Aug. 18, 2021

The importance of intramolecular constraints in cyclic transition-state geometries is especially pronounced n-endo-tet cyclizations, where the usual backside approach a nucleophile to breaking bond impossible for rings containing less than eight atoms. Herein, we expand limits endo-tet cyclizations and show that donor–acceptor cyclopropanes can provide seven-membered ring via genuine 6-endo-tet process. Substrates N-alkyl-N-arylcarbamoyl moiety as an acceptor group undergo Lewis acid-induced cyclization form tetrahydrobenz[b]azepin-2-ones high yields. reaction proceeds with inversion configuration at electrophilic carbon. In this process, formally six-membered transition state yields pre-existing cycle merged into forming ring. stereochemistry products be controlled by time nature acid, opening access both diastereomers tuning conditions.

Language: Английский

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Nickel-catalysed enantioselective reaction of secondary phosphine oxides and activated vinylcyclopropanes

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(15), P. 3096 - 3100

Published: Jan. 1, 2023

Activated vinylcyclopropanes can form zwitterionic π-allylmetal species in the presence of transition metals and are widely used organic synthesis. A nickel-catalyzed asymmetric allylation secondary phosphine oxides with was described. Tertiary oxide products could be obtained up to 91% yield 92% ee.

Language: Английский

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Asymmetric Catalytic Approaches Employing α,β‐Unsaturated Imines

European Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 26(15)

Published: Feb. 8, 2023

Abstract Nitrogen‐containing heterocyclic compounds have consistently been a noticeable center of attention due to their significant utilization in the domain synthetic organic chemistry, agrochemicals, and pharmaceuticals. α,β‐Unsaturated imines or conjugated provide lot cyclic as well acyclic products through reacting with versatile family compounds. This review summarizes recent advances enantioselective reactions α,β‐unsaturated by using methodologies for synthesizing various nitrogen‐containing heterocycles that contain four six‐membered rings. The synthesis rarely found seven‐, eight‐ nine‐membered also reported.

Language: Английский

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Asymmetric [3 + 2] cycloaddition of donor–acceptor cyclopropanes with azadienes enabled by Brønsted base catalysis

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(10), P. 2905 - 2910

Published: Jan. 1, 2024

A chiral bifunctional Brønsted base-catalyzed enantioselective [3 + 2] cycloaddition of D–A cyclopropanes and azadienes is reported. The protocol features broad substrate scope, mild reaction conditions high functional group tolerance.

Language: Английский

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Substrate-Switched Chemodivergent Pyrazole and Pyrazoline Synthesis: [3 + 2] Cycloaddition/Ring-Opening Rearrangement Reaction of Azadienes with Nitrile Imines

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(5), P. 3389 - 3401

Published: Feb. 14, 2022

By virtue of a fundamentally new reaction model benzofuran-derived azadienes (BDAs), an unprecedented synthesis biologically important pyrazoles has been achieved through tandem [3 + 2] cycloaddition/ring-opening rearrangement BDAs with nitrile imines. The nature and type substrates are found to act as chemical switch trigger two distinct pathways. A minor modification the allows access spiro-pyrazolines.

Language: Английский

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