Asymmetric Catalytic Vinylogous Addition Reactions Initiated by Meinwald Rearrangement of Vinyl Epoxides

Xu, Jinxiu; Song, Yanji; He, Jiang; Dong, Shujuan; Lin, Lili; Feng, Xiaoming

doi:10.1002/ange.202102054

Cited by 7 publications

(2 citation statements)

References 122 publications

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“…Feng and co‐workers recently achieved Lewis acid‐catalysed asymmetric vinylogous additions initiated by Meinwald rearrangement of vinyl epoxides (Scheme 7b). The key step involves a [1,2]‐hydride shift to release the allylic aldehyde, which isomerises to produce a dienolate intermediate [17d] …”

Section: Resultsmentioning

confidence: 99%

Copper‐Catalysed Rearrangement of Cyclic Ethynylethylene Carbonates: Synthetic Applications and Mechanistic Studies

Zhang

Lan

et al. 2023

Angew Chem Int Ed

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Transition-metal-catalysed reactions of cyclic ethynylethylene carbonates have been intensively studied because of their robustness in new bond formation and diversified molecule construction. Known reaction modes usually involve a substitution step occurring at either the propargylic or terminal alkyne positions. Here, we report an unprecedented reaction pattern in which cyclic ethynylethylene carbonates first undergo a rearrangement to release allenal intermediates, which subsequently react with diverse nucleophiles to furnish synthetically useful allylic and propargylic allenols, phosphorus ylides, and cyclopropylidene ketones through an addition process rather than a substitution pathway. The products enable various further transformations, and mechanistic studies and theoretical calculations reveal that the reaction does not proceed via a semipinacol type [1,2]-hydride shift, but through base-mediated deprotonation as the key step to induce the rearrangement.

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Section: Resultsmentioning

confidence: 99%

Copper‐Catalysed Rearrangement of Cyclic Ethynylethylene Carbonates: Synthetic Applications and Mechanistic Studies

Zhang

Lan

et al. 2023

Angew Chem Int Ed

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“…Several γ ‐ selective reactions to synthesize conjugate α,β‐unsaturated aldehydes, [12] and one α‐selective reaction to haloalkane [14] to synthesize non‐asymmetric α‐quaternary allyl aldehydes have been reported. Recently, the Feng group accomplished the asymmetric γ‐selective addition to satins, 2‐alkenoylpyridines and methyleneindolinones using chiral N , N ′‐dioxide‐metal catalysts, [13a] while the Deng group applied Sc/Ir dual catalysts to realize the γ‐allylation with π‐allyl Ir III species [13b] . However, there is still no example of an asymmetric α‐selective reaction involving this Meinwald rearrangement‐intermediate because of larger steric hindrance and disruption of the π‐conjugation (Scheme 1B).…”

Section: Introductionmentioning

confidence: 99%

Sterically Hindered and Deconjugative α‐Regioselective Asymmetric Mannich Reaction of Meinwald Rearrangement‐Intermediate

Song

Yang

et al. 2023

Angew Chem Int Ed

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Compared to γ‐addition, the α‐addition of α‐branched β,γ‐unsaturated aldehydes faces larger steric hindrance and disrupts the π–π conjugation, which might be why very few examples are reported. In this article, a highly diastereo‐ and enantioselective α‐regioselective Mannich reaction of isatin‐derived ketimines with α‐, β‐ or γ‐branched β,γ‐unsaturated aldehydes, generated in situ from Meinwald rearrangement of vinyl epoxides, is realized by using chiral N,N′‐dioxide/ScIII catalysts. A series of chiral α‐quaternary allyl aldehydes and homoallylic alcohols with vicinal multisubstituted stereocenters are constructed in excellent yields, good d.r. and excellent ee values. Experimental studies and DFT (density functional theory) calculations reveal that the large steric hindrance of the ligand and the Boc (tButyloxy carbonyl) protecting group of imines are critical factors for the α‐regioselectivity.

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

et al. 2022

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

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Asymmetric Catalytic Vinylogous Addition Reactions Initiated by Meinwald Rearrangement of Vinyl Epoxides

Cited by 7 publications

References 122 publications

Copper‐Catalysed Rearrangement of Cyclic Ethynylethylene Carbonates: Synthetic Applications and Mechanistic Studies

Copper‐Catalysed Rearrangement of Cyclic Ethynylethylene Carbonates: Synthetic Applications and Mechanistic Studies

Sterically Hindered and Deconjugative α‐Regioselective Asymmetric Mannich Reaction of Meinwald Rearrangement‐Intermediate

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

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