Organocatalytic Asymmetric Halocyclization of Allylic Amides to Chiral Oxazolines Using DTBM-SEGPHOS—Mechanistic Implications from Hammett Plots DOI Open Access

Fotini Moschona,

Christina Misirlaki,

Nikolaos Karadimas

et al.

Symmetry, Journal Year: 2022, Volume and Issue: 14(5), P. 989 - 989

Published: May 12, 2022

The intramolecular halocyclization of alkenes possessing an internal heteroatom nucleophile leads to multifunctional heterocycles which are useful versatile intermediates in organic synthesis. asymmetric chlorocyclisation 2-substituted allylic amides gives access chiral oxazolines bearing a chloromethyl moiety for further synthetic manipulation. literature reports on this transformation involve complex syntheses the and cryogenic temperatures achieving high enantioselectivities organocatalyzed step. Based Heck reaction aryl bromides Boc-protected allylamine or benzamides, we developed practical synthesis that does not require chromatography accomplished their with 24–92%ee under conditions (5 °C, CpME) catalyzed by (S)-(+)-DTBM-SEGPHOS. In addition, using appropriately substituted substrates, generated Hammett plots formulated consistent mechanism involves two competing modes formation haliranium intermediate whose relative kinetics governed electronic properties substrate.

Language: Английский

Electricity-driven asymmetric bromocyclization enabled by chiral phosphate anion phase-transfer catalysis DOI Creative Commons
Xuefeng Tan, Qingli Wang, Jianwei Sun

et al.

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Jan. 23, 2023

Electricity-driven asymmetric catalysis is an emerging powerful tool in organic synthesis. However, induction so far has mainly relied on forming strong bonds with a chiral catalyst. Asymmetry induced by weak interactions catalyst electrochemical medium remains challenging due to compatibility issues related solvent polarity, electrolyte interference, etc. Enabled properly designed phase-transfer strategy, here we have achieved two efficient electricity-driven catalytic bromocyclization processes ion-pairing interaction. The combined use of and phosphate catalyst, together NaBr as the bromine source, constitutes key advantages over conventional chemical oxidation approach. Synergy multiple events, including anodic oxidation, ion exchange, phase transfer, bromination, inhibition Br2 decomposition NaHCO3, proved critical success.

Language: Английский

Citations

35
Cross-assembly confined bifunctional catalysis via non-covalent interactions for asymmetric halogenation DOI Creative Commons
Tianyu Zheng, Rui Chen, Jingxian Huang

et al.

Chem, Journal Year: 2023, Volume and Issue: 9(5), P. 1255 - 1269

Published: Feb. 13, 2023

Language: Английский

Citations

19
Controlling the regioselectivity of the bromolactonization reaction in HFIP DOI Creative Commons
Tuong Anh To, Nhu T. A. Phan, Binh Khanh

et al.

Chemical Science, Journal Year: 2024, Volume and Issue: 15(19), P. 7187 - 7197

Published: Jan. 1, 2024

The halolactonization reaction provides rapid access to densely functionalized lactones from unsaturated carboxylic acids. endo/exo regioselectivity of this cyclization is primarily determined by the electronic stabilization alkene substituents, thus making it inherently dependent on substrate structures. Therefore method often affords one type halolactone regioisomer only. Herein, we introduce a simple and efficient for regioselectivity-switchable bromolactonization reactions mediated HFIP solvent. Two sets conditions were developed, each forming endo-products or exo-products in excellent regioselectivity. A combination computational experimental mechanistic studies not only confirmed crucial role HFIP, but also revealed formation under kinetic control thermodynamic control. This study paves way future work use perfluorinated solvents dictate outcomes organic synthesis.

Language: Английский

Citations

7
Intramolecular chaperone-assisted dual-anchoring activation (ICDA): a suitable preorganization for electrophilic halocyclization DOI Creative Commons
Xihui Yang,

Haowei Gao,

Jiale Yan

et al.

Chemical Science, Journal Year: 2024, Volume and Issue: 15(16), P. 6130 - 6140

Published: Jan. 1, 2024

The halocyclization reaction represents one of the most common methodologies for synthesis heterocyclic molecules. Many efforts have been made to balance relationship between structure, reactivity and selectivity, including design new electrophilic halogenation reagents utilization activating strategies. However, discovering universal or strategies remains challenging due case-by-case practice different substrates cyclization models. Here we report an intramolecular chaperone-assisted dual-anchoring activation (ICDA) model halocyclization, taking advantage non-covalent orientation as driving force. This protocol allows a practical, catalyst-free rapid approach access seven types small-sized, medium-sized, large-sized units realize polyene-like domino halocyclizations, exemplified by nearly 90 examples, risk-reducing flow gram-scale synthesis. DFT studies verify crucial role ICDA in affording suitable preorganization transition state stabilization X

Language: Английский

Citations

6
Recent Advances in Catalytic Asymmetric Syntheses of Functionalized Heterocycles via Halogenation/Chalcogenation of Carbon‐Carbon Unsaturated Bonds DOI
Shengshu Liu,

Bing‐Qian Zhang,

Wen‐Ying Xiao

et al.

Advanced Synthesis & Catalysis, Journal Year: 2022, Volume and Issue: 364(23), P. 3974 - 4005

Published: Oct. 20, 2022

Abstract Halogen (fluorine, chlorine, bromine, iodine) or chalcogen (sulfur, selenium)‐containing heterocycles are widely recognized as key building blocks in many natural products and bioactive targets. Catalytic asymmetric halogenation/chalcogenation of carbon‐carbon unsaturated bonds via onium ion transformations efficient methods to obtain diverse chiral heterocyclic backbones. In the past few years, catalytic enantioselective versions halo/thio/seleno‐functionalizations with various halogen electrophiles have experienced constant development. This review highlights those advances preparing functionalized promoted by organocatalysts metal‐based catalysts. magnified image

Language: Английский

Citations

23
Asymmetric Intermolecular Iodinative Difunctionalization of Allylic Sulfonamides Enabled by Organosulfide Catalysis: Modular Entry to Iodinated Chiral Molecules DOI
Lihao Liao,

Xinru Xu,

Jieying Ji

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(36), P. 16490 - 16501

Published: Sept. 2, 2022

Electrophilic halogenation of alkenes is a powerful transformation offering convenient route for the construction valuable functionalized molecules. However, as highly important reaction in this field, catalytic asymmetric intermolecular iodinative difunctionalization remains formidable challenge. Herein, we report that an efficient Lewis basic chiral sulfide-catalyzed approach enables reaction. By approach, challenging substrates such γ,γ-disubstituted allylic sulfonamides and 1,1-disubstituted with sulfonamide unit undergo electrophilic to give variety iodine-functionalized molecules good yields excellent enantio- diastereoselectivities. A series free phenols nucleophiles are successfully incorporated into substrates. Aside from phenols, primary secondary alcohols, fluoride, azide also serve nucleophiles. The obtained iodinated products platform molecule, which can be easily transformed various compounds α-aryl ketones, amines, aziridines via rearrangement or substitution. Mechanistic studies revealed sulfide catalyst displays superior effect on control reactivity iodine enantioselective iodiranium ion intermediate aggregates might formed resting state reactions.

Language: Английский

Citations

22
A Theoretical Study on the Mechanism of Bifunctional Brønsted Acid/Base-Catalyzed CO2-Fixation Reaction with Homoallylic Amine DOI
Yu Wang, Xin Zhang, Jia Zhou

et al.

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: 90(6), P. 2172 - 2179

Published: Jan. 31, 2025

The reaction mechanism and the enantioselectivity of Brønsted acid/base (trans-stilbene diamine, simplified by BAM)-catalyzed CO2 fixation with homoallylic amine have been investigated using density functional theory (DFT) calculations. proposed involves initial activation acid, followed nucleophilic attack on to form a carbamate intermediate. base subsequently deprotonates intermediate cyclic product, regenerating acid catalyst. C-O cyclization is enantio-determining step. hydrogen bond network formed catalyst substrate, similar an enzyme pocket, plays key role in stereoselectivity. In addition, energy decomposition analysis (EDA) confirms that bonding driven orbital electrostatic attractions. more basic BAM (OMe at quinoline 7-position) exhibits enhanced enantioselectivity.

Language: Английский

Citations

0
The literature of heterocyclic chemistry, part XXII, 2022 DOI
Галина А. Газиева, Yu. B. Evdokimenkova, N. O. Soboleva

et al.

Advances in heterocyclic chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Language: Английский

Citations

0
Asymmetric Halocyclization of 2-Anilidostyrenes Using N-Haloamides Enabled by Chiral Anion Phase-Transfer Catalysis DOI
Penghui Zhang, Xue Du, Guo-Gang Tu

et al.

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

Published: March 31, 2025

Asymmetric halogenation for efficient construction of various 4H-3,1-benzoxazine derivatives with excellent functional group tolerance using readily available N-haloamides as the halogen source and ammonium phosphate salt catalyst under mild reaction conditions has been developed. The loading could be reduced to 1 mol % recycled 4 times without deterioration in reactivity stereoselectivity. Importantly, this process features a column-purification-free operation, leading green atom-economical preparation chiral benzoxazines good yields high enantioselectivities.

Language: Английский

Citations

0
Catalytic Enantioselective Friedel–Crafts Reactions of Arenes Enabled by Iranium/Irenium-Ion-Triggered Electrophilic Functionalization DOI
Yuanyuan Zhang, Shuai Ding,

Limin Meng

et al.

Synlett, Journal Year: 2025, Volume and Issue: unknown

Published: April 14, 2025

Abstract The catalytic asymmetric Friedel–Crafts reactions of (hetero)arenes represent a cornerstone in synthetic chemistry due to their ability efficiently incorporate aromatic rings into complex molecular architectures. This account presents comprehensive overview recent advancements the enantioselective (hetero)arenes, with particular focus on that facilitate introduction multiple C–C bonds via iranium/irenium-ion-triggered electrophilic processes. We examine detail strategies and methodologies employed achieve stereoselective incorporation unsaturated bonds, highlighting construction diverse structural scaffolds. Additionally, this showcases broad range applications powerful transformation organic synthesis. 1 Introduction 2 Catalytic Enantioselective Reactions Thiiranium/Thiirenium Ions 2.1 Arylthiiranium/Arylthiirenium-Ion-Triggered 2.2 Trifluoromethylthiiranium/Trifluoromethylthiirenium-Ion-Triggered 3 Haliranium 3.1 Chloriranium-Ion-Triggered 3.2 Bromiranium-Ion-Triggered 3.3 Iodiranium-Ion-Triggered Asymmetric Oxidative Arylation Alkenes 4 Conclusion Outlook

Language: Английский

Citations

0