Tandem [4+2]/retro[3+2]/[3+2] cycloaddition reactions of fluorinated‐oxadiazoles with conjugated, unconjugated, cyclic, and acyclic dienes DOI Open Access
Joshua Atta‐Kumi, George Baffour Pipim, Ernest Opoku

et al.

Journal of Physical Organic Chemistry, Journal Year: 2023, Volume and Issue: 37(1)

Published: Oct. 2, 2023

Abstract The tandem reactions of 2,5‐bis(trifluoromethyl)‐1,3,4‐oxadiazole with conjugated, unconjugated, acyclic, and cyclic dienes have been studied at the M06‐2X/6‐311++G(d,p) level theory. rate‐determining step is initial [4+2] cycloaddition in reaction cyclic, unconjugated dienes, whereas stereochemistry adduct determined by [3+2] step. exo ‐coupling kinetically favored over endo 2,5‐(bis‐trifluoromethyl)‐1,3,4‐oxadiazole all considered dienes. In retro (N 2 extrusion), higher activation energy required to furnish carbonyl ylide conjugated as compared acyclic At step, intermolecular addition intramolecular both or proceeds low energies when are participating, those Overall, process via an asynchronous one‐step mechanism coupling ‐ ‐cycloaddition fashion, followed a [3+2], which extrudes N , then stereo‐determining leads products. polarity inter‐ intra‐molecular steps can be influenced two factors: nature heteroatom present on diene molecule size diene. These factors play role determining reactivity electron distribution within diene, thereby impacting overall reactions.

Language: Английский

Dearomative [4 + 2] cycloaddition of 3‐nitroindoles with ortho‐amino Morita−Baylis−Hillman carbonates to forge indole‐fused quinolines DOI
Kai‐Kai Wang, Yanli Li, Lanxin Li

et al.

Journal of Heterocyclic Chemistry, Journal Year: 2024, Volume and Issue: 61(3), P. 528 - 537

Published: Jan. 16, 2024

Abstract A dearomative [4 + 2] cycloaddition of 3‐nitroindoles ortho ‐amino Morita−Baylis−Hillman carbonates was established under mild conditions. This method provides an efficient and practical approach for delivering tetrahydro‐5 H ‐indolo[2,3‐ b ]quinolines containing three contiguous stereocenters, two tertiary one quaternary, in high yield (up to 95%) with excellent diastereoselectivity (all cases >25:1 dr ). The potential synthetic applications this strategy were also highlighted by the scale‐up experiment further transformation. Moreover, structure relative configuration cycloadduct unequivocally confirmed single‐crystal X‐ray diffraction.

Language: Английский

Citations

7
Substrate-controlled [4+1] and [3+2] annulations of ninhydrin-derived Morita–Baylis–Hillman carbonates to access polysubstituted furans and cyclopentenes DOI
Kai‐Kai Wang,

LI Yan-li,

Yafei Li

et al.

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(27), P. 3717 - 3720

Published: Jan. 1, 2024

The substrate-enabled switching of the regioselectivity allows for efficient regiocontrol via [4+1] and [3+2] annulations ninhydrin-derived MBH carbonates with α,β-unsaturated ketones to access highly substituted furans cyclopentene.

Language: Английский

Citations

5
Asymmetric [3 + 2] cycloaddition of donor–acceptor cyclopropanes with azadienes enabled by Brønsted base catalysis DOI
Shu Li,

Zhi-Hong Dong,

Si-Yu Dan

et al.

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

Citations

4
Phosphine-Catalyzed Cascade Cycloaddition of Vinyl Oxiranes with Sulfonium Compounds to Step-Economically Construct Spiro-2(3H)-furanone Scaffolds DOI
Thomas P. Yang, Wei Du,

Chia‐Yu Wu

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 9, 2025

In this work, we developed a phosphine-catalyzed cascade lactonization/[2 + 1] annulation reaction between vinyl oxiranes and sulfonium compounds for the highly diastereoselective construction of spiro-2(3H)-furanone skeletons. The cycloaddition proceeds via 2(5H)-furanone phosphonium intermediate, introducing an oxygen-containing active intermediate phosphine catalysis. These findings highlight significant potential harnessing as versatile synthons constructing spirocyclic through simultaneous multicyclic skeleton formation.

Language: Английский

Citations

0
Phosphine-promoted Thiol-Specific Bioconjugation with Allylic Acetates DOI Creative Commons
Teck‐Peng Loh, Xiaohong Li, Tao Xu

et al.

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: March 24, 2025

Abstract Thiol-specific modification of proteins through conjugation with small molecules represents a critical advancement in biological research and therapeutic development, particularly the context antibody-drug conjugates (ADCs) for targeted cancer therapy. Despite widespread use maleimide-based linkers, their stability under physiological conditions remains major limitation, often compromising efficacy. In this investigation, we developed novel efficient thiol-specific bioconjugation strategy that employs allylic acetate, activated by recyclable solid phosphine catalyst. This approach achieves high yields demonstrates robust bio-compatible, room-temperature conditions. Notably, it sets new record fastest cysteine-conjugation reaction rate reported to date, constant k2 = 1.49 × 106 M− 1s− 1. The method expands substrate scope introduces sustainable, environmentally friendly ADC linker design, offering significant creation stable, biocompatible, therapeutically effective compounds.

Language: Английский

Citations

0
Fluoroalkylation of Activated Allylic Acetates through Radical–Radical Coupling: Organophotoredox/DABCO Catalytic System DOI
Xiaoyu Zhang,

Yinlei Zhang,

Xiaohong Li

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(37), P. 6863 - 6868

Published: Sept. 8, 2023

A novel organophotoredox/DABCO catalytic system for the fluoroalkylation of activated allylic acetates via radical–radical coupling is described. The method offers mild reaction conditions, high selectivity, and broad substrate compatibility enabled diverse bioactive molecules, FDA-approved drugs, amino acid derivatives to be incorporated into transformation. This study expands synthetic toolbox construction fluorine-containing molecules.

Language: Английский

Citations

9
Synthesis of gem-Difluoro-3,4-dihydro-2H-pyrans via a TfOH-Catalyzed [4 + 2] Annulation of Difluoroenoxysilanes with α-Cyano Chalcones DOI
Jing Zhang,

Daokai Xiong,

Zhiwei Jiang

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(7), P. 1447 - 1451

Published: Feb. 14, 2024

Difluoroenoxysilane, a commonly used difluoroallylating reagent, has attracted considerable attention in recent years. However, its application the annulation reaction for construction of fluorinated heterocyclic compounds remains relatively limited. Presented here is Brønsted acid-catalyzed efficient formal [4 + 2] difluoroenoxysilanes with α-cyano chalcones. The developed protocol demonstrates tolerance to various substituents under mild conditions, providing reliable approach construct gem-difluoro-3,4-dihydro-2H-pyrans good excellent yields high diastereoselectivities.

Language: Английский

Citations

3
Ytterbium Triflate-Catalyzed Intramolecular Arylative Ring Opening of Arylaminomethyl-Substituted Donor–Acceptor Cyclopropanes: Access to Tetrahydroquinolines DOI

Thangaraj Devaraj,

Kannupal Srinivasan

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 20, 2024

The treatment of arylaminomethyl-substituted donor-acceptor cyclopropanes with a catalytic amount Yb(OTf)

Language: Английский

Citations

3
Phosphine-catalyzed [5+1] annulation of β′-acetoxy allenoates: straightforward access to tetrahydroquinoline derivatives DOI
Yannan Zhu,

Zhili Xu,

Yining Wang

et al.

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(78), P. 11712 - 11715

Published: Jan. 1, 2023

An unprecedented phosphine-catalyzed [5+1] annulation of β'-acetoxy allenoates with 1,5-dinucleophiles has been developed, which provides novel and facile access to functionalized tetrahydroquinolines in good high yields the presence PPh3 K3PO4 under mild reaction conditions. Notably, it is first report acting as C1 synthons Lewis base-catalyzed reactions.

Language: Английский

Citations

9
Lewis Base Controlled (4 + 3) and (4 + 2) Annulations of MBH Carbonates with Benzofuran‐derived Azadienes: Access to Highly Substituted Benzofuro[3,2‐b]azepines and Spirotetrahydroquinolines DOI
Kai‐Kai Wang,

Ya‐Fei Li,

Lanxin Li

et al.

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(21), P. 4521 - 4527

Published: Aug. 7, 2024

Abstract Catalyst‐controlled switchable (4+3) and (4+2) annulation reactions of Morita–Baylis–Hillman carbonates with benzofuran‐derived azadienes have been established. Employing PCy 3 as the catalyst, reaction could provide a variety synthetically useful benzofuro[3,2‐ b ]azepines in good yields (80–92%) excellent chemo‐ regioselectivities via cycloaddition reactions. Whereas changing catalyst from to DMAP, were switched construct highly substituted spirotetrahydroquinoline scaffolds three sequential stereocenters containing all‐carbon spiro‐quaternary efficiency diastereoselectivities (92–96% all cases>25:1 dr ) annulations. In addition, synthetic utility this method was further showcased by gram‐scale transformations product.

Language: Английский

Citations

2