Pseudo‐Stereodivergent Synthesis of Enantioenriched Tetrasubstituted Alkenes by Cascade 1,3‐Oxo‐Allylation/Cope Rearrangement

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(18), P. 7083 - 7088

Published: Feb. 19, 2020

The catalytic diastereodivergent construction of stereoisomers having two or more stereogenic centers has been extensively studied. In contrast, the switchable introduction another element, that is, Z/E configuration involving a polysubstituted alkene group, into optically active stereoisomers, not recognized yet. Disclosed here is pseudo-stereodivergent synthesis highly enantioenriched tetrasubstituted architectures from isatin-based Morita-Baylis-Hillman carbonates and allylic derivatives, under cooperative catalysis tertiary amine chiral iridium complex. success motif relies on 1,3-oxo-allylation reaction between N-allylic ylides π-allyliridium complex intermediates by ligand substrate control, followed stereoselective concerted 3,3-Cope rearrangement process.

Language: Английский

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Regio‐ and Enantioselective γ‐Allylic Alkylation of In Situ‐Generated Free Dienolates via Scandium/Iridium Dual Catalysis

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(19)

Published: Feb. 25, 2022

An unprecedented asymmetric γ-allylic alkylation of free dienolates via Sc/Ir dual catalysis is reported, which affords a range synthetically versatile crotonaldehydes in high efficiency with excellent chemo-, regio-, and enantioselectivities. The bearing no essential auxiliary groups were generated situ by scandium triflate-mediated Meinwald rearrangement vinyloxiranes atom-economically. With the assistance computational density functional theory calculations, bimetallic catalytic cycle was proposed to illustrate reaction mechanism.

Language: Английский

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Recent Advances in Catalytic [3,3]-Sigmatropic Rearrangements

Catalysts, Journal Year: 2022, Volume and Issue: 12(2), P. 227 - 227

Published: Feb. 16, 2022

Carbon–carbon bond formation by [3,3]-sigmatropic rearrangement is a fundamental and powerful method that has been used to build organic molecules for long time. Initially, Claisen Cope rearrangements proceeded at high temperatures with limited scopes. By introducing catalytic systems, highly functionalized substrates have become accessible forming complex structures under mild conditions, asymmetric synthesis can be achieved using chiral systems. This review describes recent breakthroughs in since 2016. Detailed reaction mechanisms are discussed enable an understanding of the reactivity selectivity reactions. Finally, this inspires development new cascade pathways employing as related methodologies functional molecules.

Language: Английский

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Enantioselective Synthesis of Cyclobutane Derivatives via Cascade Asymmetric Allylic Etherification/[2 + 2] Photocycloaddition

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(40), P. 21752 - 21759

Published: Sept. 28, 2023

Chiral cyclobutane presents as a popular motif in natural products and biologically active molecules, its derivatives have been extensively used key synthons organic synthesis. Herein, we report an efficient synthetic method toward enantioenriched derivatives. The reaction proceeds cascade fashion involving Ir-catalyzed asymmetric allylic etherification visible-light induced [2 + 2] cycloaddition. Readily available branched allyl acetates cinnamyl alcohols are directly the substrates under mild conditions, providing broad range of chiral cyclobutanes good yields with excellent diastereo- enantioselectivities (up to 12:1 dr, >99% ee). It is worth noting that all catalysts were simultaneously added without any separated step this approach. gram-scale diverse transformations product further enhance potential utility method.

Language: Английский

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Divergent Catalytic Approach from Cyclic Oxime Esters to Nitrogen-Containing Heterocycles with Group 9 Metal Catalysts

ACS Catalysis, Journal Year: 2018, Volume and Issue: 8(9), P. 7773 - 7780

Published: July 9, 2018

We report the divergent catalytic transformation of alkene-tethered isoxazol-5(4H)-ones by using rhodium and cobalt catalysts to afford 2H-pyrroles (with Rh catalyst) azabicyclic cyclopropanes Co catalyst). The rhodium-catalyzed 2H-pyrrole formation involving hydrogen shift is supported deuterium-labeling experiments. control experiments in cobalt-catalyzed reaction indicate that bicyclic aziridines as primary product undergo a skeletal rearrangement assisted metal iodide salts.

Language: Английский

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Isoxazol-5-ones as Strategic Building Blocks in Organic Synthesis

Synthesis, Journal Year: 2018, Volume and Issue: 50(13), P. 2473 - 2489

Published: May 17, 2018

Isoxazol-5-one rings have been identified as relevant motifs in drug candidates, agrochemicals, and materials. Furthermore, this heterocycle has also applied a versatile building block for the preparation of variety densely functionalized molecules. This short review will present most representative applications isoxazol-5-ones organic synthesis while discussing their properties reactivity. 1 Introduction 1.1 General Aspects 1.1.1 Tautomerism 1.1.2 Importance: Natural Products Isolation, Biological Activity, Materials 1.1.3 Preparation Methods 2 Isoxazol-5-ones Organic Synthesis 2.1 Reactivity 2.2 Specific Examples 2.2.1 Alkylation Strategies 2.2.2 Alkyne 2.2.3 Annulation Reactions 2.2.4 N–O Bond Insertions 2.2.4.1 1,3-Oxazin-6-ones 3 Conclusions

Language: Английский

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Recent advances of achiral and chiral diene ligands in transition-metal catalyses

Tetrahedron Letters, Journal Year: 2019, Volume and Issue: 60(37), P. 150924 - 150924

Published: July 10, 2019

Language: Английский

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Asymmetric Catalytic Formal 1,4‐Allylation of β,γ‐Unsaturated α‐Ketoesters: Allylboration/Oxy‐Cope Rearrangement

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(34), P. 11846 - 11851

Published: June 25, 2019

Abstract A highly enantioselective formal conjugate allyl addition of allylboronic acids to β,γ‐unsaturated α‐ketoesters has been realized by employing a chiral Ni II / N , ′‐dioxide complex as the catalyst. This transformation proceeds an allylboration/oxy‐Cope rearrangement sequence, providing facile and rapid route γ‐allyl‐α‐ketoesters with moderate good yields (65–92 %) excellent ee values (90–99 % ). The isolation 1,2‐allylboration products provided insight into mechanism subsequent oxy‐Cope reaction: substrate‐induced transfer Lewis acid accelerated process. Based on experimental investigations DFT calculations, rare boatlike transition‐state model is proposed origin high chirality during rearrangement.

Language: Английский

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Organocatalytic Enantioselective 1,6‐aza‐Michael Addition of Isoxazolin‐5‐ones to p‐Quinone Methides

European Journal of Organic Chemistry, Journal Year: 2020, Volume and Issue: 2020(5), P. 627 - 630

Published: Jan. 7, 2020

A thiourea‐Brønsted base bifunctional catalyst allowed the enantioselective 1,6‐ aza ‐Michael addition of isoxazolin‐5‐ones to p ‐quinone methides give having a chiral diarylmethyl moiety attached N atom with fair good yields and enantiomeric excesses. To best our knowledge this reaction represents first example ‐alkylation as well involving methides.

Language: Английский

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Iridium-catalyzed enantioselective direct vinylogous allylic alkylation of coumarins

Chemical Science, Journal Year: 2018, Volume and Issue: 9(26), P. 5767 - 5772

Published: Jan. 1, 2018

The first iridium-catalyzed enantioselective vinylogous allylic alkylation of coumarins is presented. Using easily accessible linear carbonates as the electrophile, this reaction installs unfunctionalized allyl groups at γ-position 4-methylcoumarins in an exclusively branched-selective manner generally high yields with excellent level enantioselectivity (up to 99 : 1 er).

Language: Английский

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