π‐Lewis‐Base‐Catalyzed Asymmetric Vinylogous Umpolung Reactions of Cyclopentadienones and Tropone

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(51), P. 26762 - 26768

Published: Oct. 8, 2021

We disclose that the carbonates of 4-hydroxy-2-cyclopentenones can form π-allylpalladium-based 1,2-carbodipoles, which isomerize to interesting η2 -Pd0 -cyclopentadienone complexes. Compared with labile parent cyclopentadienone, HOMO energy related -complex was significantly raised via back-bonding Pd0 as a π-Lewis base, rendering uncoordinated C=C bond an electron-richer dienophile in inverse-electron-demand aza-Diels-Alder-type reactions diverse 1-azadienes. The vinylogous (aza)Morita-Baylis-Hillman or cross Rauhut-Currier addition (imine)carbonyls activated alkenes, respectively, also realized afford chiral [4+2] [2+2] cycloadducts, after trapping re-generated π-allylpalladium species. New C1 -symmetric ligands from simple sources were developed, exhibiting high stereoselectivity even racemic substrates unusual dynamic kinetic resolution process. Besides, tropone could be similarly by complex.

Language: Английский

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Stereodivergent synthesis of enantioenriched azepino[3,4,5-cd]-indoles via cooperative Cu/Ir-catalyzed asymmetric allylic alkylation and intramolecular Friedel–Crafts reaction

Chemical Science, Journal Year: 2022, Volume and Issue: 13(17), P. 4801 - 4812

Published: Jan. 1, 2022

A stereodivergent synthesis of azepino[3,4,5- cd ]-indoles bearing three stereogenic centers was established via synergistic dual-metal catalysis followed by acid-promoted epimerization, and up to all eight stereoisomers could be predictably achieved.

Language: Английский

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Catalytic Enantioselective [3+2] Cycloaddition of N‐Metalated Azomethine Ylides

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(28)

Published: March 7, 2023

Abstract Asymmetric [3+2] cycloaddition reactions are fascinating and powerful methods for the synthesis of enantioenriched pyrrolidines up to four stereocentres. Pyrrolidines important compounds both biology organocatalytic applications. This review summarizes most recent advances in enantioselective by cycloadditions azomethine ylides using metal catalysis. It has been organized type catalysis used further arranged complexity nature dipolarophile. The presentation each reaction highlights their advantages limitations.

Language: Английский

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β-Substituted Alkenyl Heteroarenes as Dipolarophiles in the Cu(I)-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition of Azomethine Ylides Empowered by a Dual Activation Strategy: Stereoselectivity and Mechanistic Insight

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(9), P. 3519 - 3535

Published: March 1, 2021

The catalytic asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides with various electron-deficient alkenes provide the most straightforward protocol for preparation enantioenriched pyrrolidines in organic synthesis. However, employment conjugated alkenyl heteroarenes as dipolarophiles such protocols to afford a class particularly important molecules medicinal chemistry is still great challenge. Herein, we report that β-substituted heteroarenes, challenging internal alkene substrates without strong electron-withdrawing substituent, were successfully employed first time Cu(I)-catalyzed ylides. This reaction furnishes large array multistereogenic heterocycles incorporating both biologically pyrrolidine and heteroarene skeletons good yields exclusive diastereoselectivity excellent enantioselectivity. Our extensive density functional theory (DFT) calculations proposed working model explain origin stereochemical outcome elucidated uncommon dual activation/coordination dipole dipolarophile by metal, which sterically bulky, rigid, monodentate phosphoramidite ligand triple-homoaxial chirality plays pivotal role providing an effective chiral pocket around metal center, resulting high additional coordination heteroatom substrate Cu also critical enhanced reactivity. predicted reverse enantioinduction corresponding monocyclic well regiospecific less reactive C═C bond one related diene substrate. Such unique steric effect-directed enantioswitching coordination-directed regioselectivity verified experimentally.

Language: Английский

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Recent advances in the (3+2) cycloaddition of azomethine ylide

New Journal of Chemistry, Journal Year: 2023, Volume and Issue: 47(19), P. 8997 - 9034

Published: Jan. 1, 2023

We have tried to demonstrate [3+2] cycloaddition of azomethine ylides for the synthesis several bioactive compounds. Different methodologies, including metal-catalyzed as well metal-free asymmetric and racemic synthesis, been explained.

Language: Английский

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Catalytic Asymmetric Dearomative 1,3-Dipolar Cycloaddition of 2-Nitrobenzothiophenes and Isatin-Derived Azomethine Ylides

Organic Letters, Journal Year: 2021, Volume and Issue: 23(21), P. 8600 - 8605

Published: Oct. 21, 2021

An enantioselective dearomative 1,3-dipolar cycloaddition of 2-nitrobenzothiophenes and isatin-derived azomethine ylides with a bifunctional hydrogen-bonding thiourea catalyst was established, giving polyheterocyclic compounds in excellent results (up to 99% yield, >20:1 dr for all cases up ee). The enantioselectivity could be reversed by the squaramide containing same chiral source as catalyst. DFT calculations revealed origin observed stereochemistry reversal enantioselectivity.

Language: Английский

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Recent Dearomatization Strategies of Benzofurans and Benzothiophenes

Asian Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 10(5), P. 932 - 948

Published: March 10, 2021

Abstract This review article discusses about the recent developments in area of strategies for dearomatization benzofurans and benzothiophenes (2010–2020). The readers can understand current state art this intriguingly important organic synthesis generation diversely functionalized molecules, polycyclic systems from highly abundant benzothiophenes. We hope that would help synthetic community design development new as well further growth novel rapidly growing research.

Language: Английский

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Iridium-Catalyzed Diastereo- and Enantioselective [4 + 3] Cycloaddition of 4-Indolyl Allylic Alcohols with Azomethine Ylides

Organic Letters, Journal Year: 2021, Volume and Issue: 23(2), P. 588 - 594

Published: Jan. 6, 2021

An unprecedented iridium-catalyzed asymmetric [4 + 3] cycloaddition of racemic 4-indolyl allylic alcohols with azomethine ylides is reported. The ability acid promoter zinc triflate to perform multiple roles the key factor for success this strategy. This method provides scalable and efficient access biologically important azepino[3,4,5-cd] indoles in good yields generally excellent diastereo- enantioselectivities (up >20:1 dr >99% ee). Mild reaction conditions, easily accessible substrates chiral catalyst, broad substrate scope highlight practicality methodology.

Language: Английский

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Synergistic Catalysis between a Dipeptide Phosphonium Salt and a Metal‐Based Lewis Acid for Asymmetric Synthesis ofN‐Bridged [3.2.1] Ring Systems

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(38)

Published: June 29, 2022

Abstract We present an unprecedented synergic catalytic route for the asymmetric construction of fluorinated N ‐bridged [3.2.1] cyclic members tropane family via a bifunctional phosphonium salt/silver co‐catalyzed cyclization process. A broad variety substrates bearing assortment functional groups are compatible with this method, providing targeted compounds seven‐membered ring and four contiguous stereocenters in high yields excellent stereoselectivities. The gram‐scale preparations, facile elaborations preliminary biological activities products demonstrate application potential. Moreover, both experimental computational mechanistic studies revealed that proceeded “sandwich” reaction model multiple weak‐bond cooperative activations. Insights gained from our expected to advance general efforts towards synthesis challenging chiral heterocyclic molecules.

Language: Английский

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Copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of 1,3-enynes and azomethine ylides

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

Published: Aug. 4, 2023

Herein, we report a copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides and 1,3-enynes, which provides series chiral poly-substituted pyrrolidines in high regio-, diastereo-, enantioselectivities. Both 4-aryl-1,3-enynes 4-silyl-1,3-enynes serve as suitable dipolarophiles while 4-alkyl-1,3-enynes are inert. Moreover, the method is successfully applied construction both tetrasubstituted stereogenic carbon centers spiro pyrrolidines. The DFT calculations also conducted, imply concerted mechanism rather than stepwise mechanism. Finally, various transformations started from pyrrolidine bearing triethylsilylethynyl group centered on alkyne achieved, compensates for inertness present reaction.

Language: Английский

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