Copper-catalyzed asymmetric 1,6-conjugate addition of in situ generated para-quinone methides with β-ketoesters

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(46), P. 6653 - 6656

Published: Jan. 1, 2022

A Cu-catalyzed asymmetric 1,6-conjugate addition of in situ generated para-quinone methides (p-QMs) with β-ketoester has been developed to construct a ketoester skeleton bearing an adjacent tertiary-quaternary carbon stereocenter good yields and high enantioselectivities. This is the first example metal-catalyzed transformations p-QMs, avoiding using pre-synthesized p-QMs requiring bulky 2,6-substitutions highlighting new dual catalytic activation chiral bis(oxazoline)-metal complex acting as normal Lewis acid activate β-ketoesters source Brønsted responsible for generating situ.

Language: Английский

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Recent advances in Pd-catalyzed asymmetric cyclization reactions

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 53(2), P. 883 - 971

Published: Dec. 18, 2023

This review aims to collect advancements in enantioselective palladium-catalyzed cyclization reactions over the past eleven years, and it is organized into thirteen sections depending on different types of transformations involved.

Language: Английский

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Synthesis of Fluorine-Containing Multisubstituted Oxa-Spiro[4,5]cyclohexadienones via a Fluorinated Alcohol-Catalyzed One-Pot Sequential Cascade Strategy

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(5), P. 2847 - 2857

Published: Feb. 16, 2024

In recent years, the application of fluorinated alcohols as solvents, cosolvents, or additives has become important in modern organic synthesis. However, their potential efficient catalysts synthesis not been well-explored. this article, we report on development a one-pot sequential cascade reaction p-quinone methides with difluoroenoxysilanes using hexafluoroisopropanol catalyst. This allows for preparation multisubstituted oxa-spiro[4,5]cyclohexadienones. By 50 mol % 1,1,1,3,3,3-Hexafluoroisopropanol (HFIP), proceeds smoothly to yield 1,6-conjugated products, which are then subjected oxidative dearomatization/hemiacetalization PhI(OAc)2. The overall process affords moderate high yields and excellent diastereoselectivities.

Language: Английский

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P(NMe₂)₃-Mediated Umpolung Spirocyclopropanation Reaction of p-Quinone Methides: Diastereoselective Synthesis of Spirocyclopropane-Cyclohexadienones

Organic Letters, Journal Year: 2020, Volume and Issue: 22(21), P. 8376 - 8381

Published: Oct. 12, 2020

An unprecedented umpolung spirocyclopropanation reaction of p-quinone methides and α-keto carbonyls is described. Our strategy based on 1,6-conjugate addition intramolecular nucleophilic substitution offers a new method for effective access to series highly functionalized spirocyclohexadienonyl cyclopropanes having two vicinal quaternary carbons in ≤98% yield >20:1 dr. Significantly, cyclic acyclic topological structures as 1,1-dipole one-carbon synthons have distinct influence the stereochemistry products, showing reversal diastereoselectivity this P(NMe2)3-mediated spirocyclopropanation.

Language: Английский

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Sulfone as a Transient Activating Group in the Palladium-Catalyzed Asymmetric [4 + 3] Cycloaddition of Trimethylenemethane Enabling the Enantioselective Synthesis of Fused Azepines

Organic Letters, Journal Year: 2021, Volume and Issue: 23(3), P. 948 - 952

Published: Jan. 22, 2021

The palladium-catalyzed asymmetric [4 + 3] cycloaddition of a sulfonyl-trimethylenemethane (TMM) donor with azadienes furnished various sulfonyl-fused azepines exclusive regioselectivities and excellent stereoselectivities (up to >20:1 dr, >99% ee) in high yields 93%). Moreover, sulfone, serving as transient activating group the TMM species, can be easily removed from cycloadducts provide structurally simple fused enantioselectivities. This strategy demonstrates sulfonyl-TMM an effective surrogate naked reactivity, regioselectivity, stereoselectivity.

Language: Английский

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Recent advances in the cyclization of para-quinone methides

Tetrahedron, Journal Year: 2023, Volume and Issue: 148, P. 133655 - 133655

Published: Oct. 9, 2023

Language: Английский

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Palladium‐Catalyzed [4+2] Cycloaddition of Hydroxy‐Tethered Allylic Carbonates with Alkenes: Synthesis of Functionalized Tetrahydropyrans

Advanced Synthesis & Catalysis, Journal Year: 2022, Volume and Issue: 364(12), P. 2060 - 2066

Published: May 5, 2022

Abstract A palladium‐catalyzed [4+2] cycloaddition of hydroxy‐tethered allyl carbonates with five types electron‐deficient alkenes has been achieved, in which a type new acted as valuable precursors for the formation 1,4‐C,O‐dipole allylpalladium intermediates. The reaction proceeded efficiently under mild conditions to provide corresponding tetrahydropyran derivatives moderate high yields excellent diastereoselectivities. magnified image

Language: Английский

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Palladium‐Catalyzed (5+3) Annulation of 4‐Vinyl‐4‐Butyrolactones with C,N‐Cyclic Azomethine Imines: Construction of Eight‐Membered Ring

Advanced Synthesis & Catalysis, Journal Year: 2022, Volume and Issue: 364(22), P. 3967 - 3972

Published: Oct. 18, 2022

Abstract In this paper, we designed and synthesized 4‐vinyl‐4‐butyrolactone as a precursor to generate the zwitterionic allylpalladium intermediates, which behaved five‐membered all‐carbon synthon in palladium‐catalyzed (5+3) annulation with azomethine imines, giving eight‐membered ring‐fused heterocycles (26 examples, 49% 97% yield, >20:1 dr). magnified image

Language: Английский

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One-Pot Domino Catalysis to Construct Alkyl/Aryl Pyrroles Initiated by Pd-TMM Annulation of Unactivated Imines

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

Published: Jan. 9, 2025

Herein, a one-pot domino catalyzed three-component process is described, which initiated by palladium/zinc cooperatively cycloaddition between trimethylenemethane (TMM) and unactivated alkyl/aryl imines, followed isomerization Zn(OTf)2-catalyzed DDQ oxidation, furnishing valuable substituted pyrroles. We disclose that the cooperative catalysis affords dual-Zn(OTf)2-stabilized azapalladacycle, wherein Pd–N bond polarized Zn(OTf)2, facilitating unique outer-sphere allylic amination. Moreover, subsequent dehydrogenation can be feasibly promoted zinc catalysis.

Language: Английский

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A new type of δ-vinylvalerolactone for palladium-catalyzed cycloaddition: synthesis of nine-membered heterocycles

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(46), P. 6646 - 6649

Published: Jan. 1, 2022

In this paper, a new type of δ-vinylvalerolactone was designed and synthesized, used as precursor in Pd-catalyzed [6+3] cycloaddition with azomethine imines, leading to nine-membered 1,2-dinitrogen-containing heterocycles 77-98% yields >20 : 1 d.r. These ring-fused products were further transformed into unusual tetracyclic bridged-ring compounds without loss the diastereoselectivities.

Language: Английский

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