Iridium-Catalyzed Intramolecular Asymmetric Allylic Dearomatization Reaction of Pyridines, Pyrazines, Quinolines, and Isoquinolines

Journal of the American Chemical Society, Journal Year: 2015, Volume and Issue: 137(50), P. 15899 - 15906

Published: Nov. 25, 2015

The first Ir-catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines, pyrazines, quinolines, and isoquinolines has been developed. Enabled by in situ formed chiral Ir-catalyst, the dearomatized products were isolated high levels yield (up to 99% yield) enantioselectivity ee). It is worth noting that Me-THQphos ligand much more efficient than other tested ligands for pyrazines certain quinolines. Mechanistic studies carried out, results suggest feasibility an alternative process which features formation a quinolinium as key intermediate. mechanistic findings render this yet unknown type chemistry Reissert-type reactions. In addition, utility method was showcased large-scale formal synthesis (+)-gephyrotoxin.

Language: Английский

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Palladium-Catalyzed Asymmetric Allylic Alkylation of 3-Substituted 1H-Indoles and Tryptophan Derivatives with Vinylcyclopropanes

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(21), P. 6710 - 6717

Published: May 11, 2018

Vinylcyclopropanes (VCPs) are known to generate 1,3-dipoles with a palladium catalyst that initially serve as nucleophiles undergo [3 + 2] cycloadditions electron-deficient olefins. In this report, we reverse reactivity and drive the electrophiles by employing 3-alkylated indoles nucleophiles. This represents first use of VCPs for completely atom-economic functionalization 3-substituted 1 H-indoles tryptophan derivatives via Pd-catalyzed asymmetric allylic alkylation (Pd-AAA). Excellent yields high chemo-, regio-, enantioselectivities have been realized, providing various indolenine indoline products. The method is amenable gram scale works efficiently contain diketopiperazine or diketomorpholine ring, allowing us synthesize mollenine A in rapid ligand-controlled fashion. obtained products bear an imine, internal olefin, malonate motif, giving multiple sites diverse reactivities product diversification. Complicated polycyclic skeletons can be conveniently constructed leveraging unique juxtaposition functional groups.

Language: Английский

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Ir-Catalyzed Asymmetric Total Synthesis of (−)-Communesin F

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(9), P. 3364 - 3367

Published: Feb. 21, 2017

The first catalytic asymmetric total synthesis of the heptacyclic alkaloid (-)-communesin F is described. A key step features an iridium-catalyzed intermolecular cascade cyclization, constructing lower N,N-aminal-containing CDEF tetracyclic core in one step. Another notable element closure final ring system (A ring) via a facile reduction twisted amide and concomitant cyclization activated by mesylation N,O-hemiaminal intermediate.

Language: Английский

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Enantioselective γ-Alkylation of α,β-Unsaturated Malonates and Ketoesters by a Sequential Ir-Catalyzed Asymmetric Allylic Alkylation/Cope Rearrangement

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(16), P. 5234 - 5237

Published: April 7, 2016

A catalytic, enantioselective γ-alkylation of α,β-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- iridium-catalyzed α-alkylation an extended enolate, subsequent translocation chirality to the γ-position via Cope rearrangement.

Language: Английский

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Enantioselective Synthesis of 3a‐Amino‐Pyrroloindolines by Copper‐Catalyzed Direct Asymmetric Dearomative Amination of Tryptamines

Angewandte Chemie International Edition, Journal Year: 2015, Volume and Issue: 55(2), P. 751 - 754

Published: Nov. 25, 2015

Abstract A direct asymmetric dearomative amination of tryptamines with O‐(2,4‐dinitrophenyl)hydroxylamine (DPH) was achieved using CuBr‐bisoxazoline complex as a catalyst, affording 3a‐amino‐pyrroloindolines in good to excellent enantioselectivity under mild reaction conditions. Furthermore, the synthetic value this method demonstrated total synthesis (−)‐psychotriasine highly concise manner.

Language: Английский

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Catalyst-Controlled Chemoselective and Enantioselective Reactions of Tryptophols with Isatin-Derived Imines

ACS Catalysis, Journal Year: 2017, Volume and Issue: 7(10), P. 6984 - 6989

Published: Sept. 13, 2017

Catalyst-controlled chemoselective and enantioselective reactions of tryptophols with isatin-derived imines were demonstrated. Under catalysis a chiral phosphoric acid, diastereoselective dearomative cyclization occurred, while, in the presence squaramide-tertiary amine, addition occurred. Both afforded 3-substituted 3-amino-oxindoles generally good yields (up to 99%) excellent stereoselectivities >95:5 dr, 99:1 er).

Language: Английский

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Palladium(0)-Catalyzed Dearomative [3 + 2] Cycloaddition of 3-Nitroindoles with Vinylcyclopropanes: An Entry to Stereodefined 2,3-Fused Cyclopentannulated Indoline Derivatives

Organic Letters, Journal Year: 2017, Volume and Issue: 19(9), P. 2266 - 2269

Published: April 18, 2017

The palladium(0)-catalyzed diastereoselective dearomative cyclopentannulation of 3-nitroindoles with vinylcyclopropanes is described. This straightforward and highly atom-economical method leads to a wide range functionalized indolines in good yields diastereoselectivities represents an unprecedented entry toward the valuable 2,3-fused cyclopentannulated indoline scaffold.

Language: Английский

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A catalytic asymmetric construction of a tetrahydroquinoline-based spirooxindole framework via a diastereo- and enantioselective decarboxylative [4+2] cycloaddition

Chemical Communications, Journal Year: 2017, Volume and Issue: 53(72), P. 10030 - 10033

Published: Jan. 1, 2017

A catalytic asymmetric decarboxylative [4+2] cycloaddition of vinyl benzoxazinanones with methyleneindolinones has been established, which provided a series chiral tetrahydroquinoline-based 3,3'-spirooxindoles in high yields (up to 96%) and excellent diastereo- enantioselectivities (all >95 : 5 d.r., up 99% ee). This reaction not only represents the first example enantioselective between Pd-containing 1,4-dipoles, but also demonstrates great practicability cycloadditions synthesis enantio-enriched polycyclic compounds.

Language: Английский

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Sequence‐Dependent Stereodivergent Allylic Alkylation/Fluorination of Acyclic Ketones

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(5), P. 2039 - 2043

Published: Nov. 6, 2019

Abstract The stereodivergent iridium‐catalyzed allylic alkylation and fluorination of acyclic ketones is described. α‐Pyridyl‐α‐fluoroketones with vicinal tertiary quaternary stereocenters were obtained in moderate to excellent yields stereoselectivities. Distinct from known synthesis, for which two different chiral catalysts are required general, herein we report a sequence‐dependent synthesis. With only single Ir catalyst, all four possible stereoisomers the products prepared same starting materials by simply adjusting sequence asymmetric varying absolute configuration catalyst.

Language: Английский

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Highly efficient synthesis and stereoselective migration reactions of chiral five-membered aza-spiroindolenines: scope and mechanistic understanding

Chemical Science, Journal Year: 2016, Volume and Issue: 7(7), P. 4453 - 4459

Published: Jan. 1, 2016

An Ir-catalyzed asymmetric synthesis of five-membered aza-spiroindolenines is achieved. Based on the detailed investigation reaction patterns aryl iminium migration, a one-pot allylic dearomatization/migration sequence from racemic indole derivatives realized, affording enantioenriched Pictet-Spengler-type products bearing an additional stereogenic center adjacent to C3 position core.

Language: Английский

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