Asymmetric Domino Heck/Dearomatization Reaction of β-Naphthols to Construct Indole–Terpenoid Frameworks

Organic Letters, Journal Year: 2021, Volume and Issue: 23(20), P. 7865 - 7872

Published: Sept. 28, 2021

A palladium-catalyzed enantioselective Heck cyclization/dearomatization cascade via capturing the cyclized π-allylpalladium intermediate by β-naphthols is reported, which provides a new strategy for construction of chiral indole-terpenoid frameworks. This method affords indole-functionalized β-naphthalenone compounds bearing an all-carbon-substituted quaternary center in excellent yields (up to 92%) and enantioselectivities 94% ee). In addition, utility this showcased gram-scale syntheses diverse transformations dearomatized products.

Language: Английский

Bifunctinoal Phosphonium Salt‐Catalyzed Asymmetric Cyclodearomatization of 2‐Nitroindoles and 2‐Nitrobenzofurans for Constructing CF₃‐Containing Spiro‐Polycycles

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 363(12), P. 3115 - 3120

Published: April 13, 2021

Abstract An efficient enantioselective dearomative cycloaddition reaction between either 2‐nitroindoles or 2‐nitrobenzofurans and N ‐2,2,2‐trifluoroethylisatin ketimines by dipeptided phosphonium salt catalysis is firstly established. This protocol provides a new facile synthetic approach to create variety of CF 3 ‐containing polycyclic spirooxindole derivatives under mild conditions with high yields in excellent diastereo‐ enantioselectivities (all >20:1 dr , up 95% ee). magnified image

Language: Английский

Enantioselective Synthesis of Multifunctionalized 4H-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis

Organic Letters, Journal Year: 2019, Volume and Issue: 22(2), P. 395 - 399

Published: Dec. 31, 2019

A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional phosphonium salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- enantioselectivities >20:1 dr, up >99.9% ee). The utility the practicality method demonstrated by gram-scale reaction facile elaboration. Of note, is first example an asymmetric allenic reactants phase-transfer catalysis system.

Language: Английский

Catalytic Enantioselective Dearomatization/Rearomatization of 2-Nitroindoles to Access 3-Indolyl-3′-Aryl-/Alkyloxindoles: Application in the Formal Synthesis of Cyclotryptamine Alkaloids

Organic Letters, Journal Year: 2020, Volume and Issue: 22(18), P. 7088 - 7093

Published: Aug. 28, 2020

The first catalytic enantioselective dearomatization/rearomatization of 2-nitroindoles triggered by the Michael addition 3-monosubstituted oxindoles was established. A wide range 3-indolyl-3'-alkyloxindoles (up to 99% yield, 97% ee) and 3-indolyl-3'-aryloxindoles 95% were obtained using an organocatalyst. This method provides unprecedented strategy access structurally diverse 3,3'-disubstituted bearing a sterically congested triaryl-containing all-carbon quaternary stereocenter. utility this approach verified formal synthesis cyclotryptamine alkaloids.

Language: Английский

Dinuclear Zinc Catalyzed Enantioselective Dearomatization [3+2] Annulation of 2‐Nitrobenzofurans and 2‐Nitrobenzothiophenes

Chemistry - A European Journal, Journal Year: 2021, Volume and Issue: 28(2)

Published: Oct. 29, 2021

The application of dinuclear zinc catalysts in a dearomatization reaction has been developed. Catalytic asymmetric [3+2] annulations 2-nitrobenzofurans or 2-nitrobenzothiophenes with CF3 -containing N-unprotected isatin-derived azomethine ylides catalyzed by are realized excellent diastereomer ratios (dr) >20 : 1 and enantiomeric excess (ee) up to 99 %. This protocol provides practical, straightforward access structurally diverse pyrrolidinyl spirooxindoles containing 2,3-fused-dihydrobenzofuran (or dihydrobenzothiphene) moiety, four contiguous stereocenters. Reactions can be performed on gram scale. absolute configuration products is confirmed X-ray single crystal structure analysis, possible mechanism proposed.

Language: Английский

Dearomatization of Nitro(hetero)arenes through Annulation

European Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 2022(18)

Published: April 5, 2022

Abstract Dearomatization reactions employing simple aromatic compounds have showcased remarkable progress in the recent decade and emerged as one of most straightforward powerful tools for creation highly functionalized, three‐dimensional molecular frameworks commonly encountered medicinal chemistry life sciences. Among use, nitro(hetero)arenes, which feature a less pronounced character due to presence electron‐withdrawing nitro group, been extensively used different types dearomatization reactions. The dearomative annulation reaction serves versatile method construction complex polycyclic systems. This overview presents brief summary impressive advances nitro(hetero)arenes provides some inspirations future research.

Language: Английский

Organocatalyzed asymmetric dearomative 1,3‐dipolar cycloaddition of 2‐nitrobenzofurans and N‐2,2,2‐trifluoroethylisatin ketimines

Chirality, Journal Year: 2022, Volume and Issue: 34(7), P. 1019 - 1034

Published: May 6, 2022

Abstract A readily available chiral cyclohexanediamine‐derived bifunctional tertiary amine‐squaramide catalyst is more effective for the asymmetric dearomative 1,3‐dipolar cycloaddition of 2‐nitrobenzofurans and N ‐2,2,2‐trifluoroethylisatin ketimines. range structurally diverse spiro‐fused polyheterocyclic compounds containing oxindole, pyrrolidine, hydrobenzofuran motifs were smoothly obtained in excellent results (up to 99% yield, >20:1 dr all cases up ee). This method features high efficiency, mild reaction conditions, exquisite induction, wide functional group tolerance, great potential scale‐up synthesis, attractive product diversification.

Language: Английский

Palladium(0)-Catalyzed Intermolecular Asymmetric Allylic Dearomatization of Substituted β-Naphthols with Morita–Baylis–Hillman (MBH) Adducts

Organic Letters, Journal Year: 2022, Volume and Issue: 24(43), P. 8031 - 8035

Published: Oct. 20, 2022

Pd-catalyzed intermolecular asymmetric allylic dearomatization of substituted β-naphthol derivatives with Boc-protected Morita-Baylis-Hillman (MBH) adducts was developed. The reaction occurs smoothly in 1,4-dioxane at room temperature the presence [Pd(C3H5)Cl]2 (2.5 mol %), (S, Sp)-PHOX ligand (5.5 and Li2CO3 (1.0 equiv). A series dearomatized products were afforded moderate to excellent yields enantioselectivity (up 99% yield, 97% ee). Furthermore, compatibility gram-scale mild conditions make current method synthetically useful.

Language: Английский

Enantioselective [3 + 2] annulation of 3-hydroxymaleimides with quinone monoimines

Organic Chemistry Frontiers, Journal Year: 2021, Volume and Issue: 8(10), P. 2268 - 2273

Published: Jan. 1, 2021

Enantioselective [3 + 2] annulation of 3-hydroxymaleimides with quinone monoimines provided a large variety succinimide fused indolines in moderate to good yields enantioselectivities.

Language: Английский

1,3-Dipolar Cycloadditions Involving Allenes: Synthesis of Five-Membered Rings

Current Organic Chemistry, Journal Year: 2019, Volume and Issue: 23(27), P. 3064 - 3134

Published: Dec. 4, 2019

The 1,3-dipolar cycloaddition reaction is a powerful and versatile strategy for the synthesis of carbocyclic heterocyclic five-membered rings. Herein, most recent developments on [3+2] reactions using allenes acting either as dipolarophiles or 1,3-dipole precursors, are highlighted. contributions phosphine- transition metal-catalyzed annulations involving substrates also covered, with exception those in which formation (or synthetic equivalent) not invoked. This review summarizes relevant research used building blocks construction structurally diverse rings via annulation reactions.

Language: Английский