Umpolung of donor–acceptor cyclopropanes<i>via</i>N-heterocyclic carbene organic catalysis

Nie, Guihua; Huang, Xuan; Wang, Zhongyao; Pan, Dingwu; Zhang, Junmin; Robin, Yonggui

doi:10.1039/d1qo00826a

Cited by 11 publications

(6 citation statements)

References 69 publications

(5 reference statements)

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“…For oxidant-free redox [3 + 2] annulation, the reducible aldehydes are employed [170][171][172][173][174][175][176][177][178][179][180]. The NHC-linked homoenolate derivatives act as a C3 synthon for [3 + 2] annulation [170][171][172][173][174][175][176][177][178].…”

Section: [3 + 2] Annulationmentioning

confidence: 99%

NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

Yamaoka,

Miyabe

2024

Catalysts

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In the past few decades, N-heterocyclic carbenes (NHCs) have opened the new field of organocatalysis in synthetic organic chemistry. This review highlights the dramatic progress in the field of NHC-catalyzed C–O bond formation based on the activation of aldehyde C(sp2)–H bonds. The oxidative and redox transformations for the synthesis of various molecules with structural diversity and complexity are summarized. Furthermore, new methods and strategies for NHC catalysis are emerging continuously; thus, cooperative catalysis with Brønsted acid, hydrogen-bonding catalyst, transition-metal catalyst, and photocatalyst are also described.

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Section: [3 + 2] Annulationmentioning

confidence: 99%

NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

Yamaoka,

Miyabe

2024

Catalysts

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“…Chi and co-workers in 2021 disclosed a Umpolung reaction of DAC containing an acetyl aldehyde in presence of Nheterocyclic carbene catalyst 163 with isatin leading to spirolactone 162 via the (3+2) cycloaddition reaction (Scheme 33). 67 In this reaction, the β-carbon of the 2cyclopropylacetaldehyde 160 is dipole inverted to a nucleophile through formation of acyl azolium and undergoes (3+2) cycloaddition with isatins with high enantio-and diastereoselectivity.…”

Section: Template For Synthesis Thiemementioning

confidence: 99%

“…In 2021, Chi and co-workers reported the Umpolung reaction of DAC-acetaldehydes 160 in the presence of N -heterocyclic carbene catalyst 163 with isatins leading to spirolactone 162 via a (3+2) cycloaddition reaction (Scheme 33 ). 67 In this reaction, the β-carbon of the cyclopropane-2-acetaldehyde 160 is dipole inverted to a nucleophile through formation of acyl azolium and undergoes (3+2) cycloaddition with isatins with high enantio- and diastereoselectivity. Mechanistically, the cyclopropane-2-carbaldehyde 160 isomerizes to the enal 167 in the presence of NHC catalyst via pathway A or alternatively a direct activation occurs via pathway B.…”

Section: Synthesis Of Oxygen Heterocyclesmentioning

confidence: 99%

Synthesis of Heterocycles from Donor-Acceptor Cyclopropanes: A Five-Year Recap

Deepthi¹,

Meenakshy²,

Mohan³

2023

Synthesis

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The utility of donor-acceptor cyclopropanes (DACs) for the construction of heterocycles is discussed here. In addition to (3+2), (3+3) and (4+3) cycloaddition pathways, nucleophilic ring-opening reactions, intramolecular transformations and cycloisomerizations in presence of suitable catalysts pave way for the generation of heterocycles from DACs. Mild reactions conditions employed and the variety of starting materials that can be used as reaction partners makes the DAC route for heterocycle synthesis attractive. The literature from 2018-2023 is categorized as below. 1 Introduction 2 Synthesis of Nitrogen heterocycles 2.1 By annulations with anthranils and azadienes 2.2 By nucleophilic attack of anilines and hydrazones 2.3 By reaction with ureas and thioureas 2.4 By annulation reactions using azomethine imine 2.5 By reaction with other N-heterocycles 2.6 By other transformations 3 Synthesis of Oxygen heterocycles 3.1 By intramolecular transformations 3.2 By intermolecular reactions 4 Synthesis of Sulphur/Selenium heterocycles 4.1 By reaction with thiocarbonyl substrates 4.2 By reaction with thio/selenocyanates and thiosulfonate salts 5 Synthesis of N-S/O heterocycles 6 Conclusions

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“…In 2021, Chi and co‐workers reported an NHC‐catalyzed umpolung activation protocol for the cycloaddition reaction between the donor‐acceptor (D−A) cyclopropane 84 and the isatin substrate 85 (Scheme 15a) [28] . The chiral spirocyclic lactone 86 bearing a tetra‐substituted stereogenic center could be formed in a good yield with excellent enantio‐ and diastereoselectivities.…”

Section: Nhc‐catalyzed Homo Activation Reactions Of Cyclopropanes And...mentioning

confidence: 99%

N‐Heterocyclic Carbene‐Catalyzed Activation of 3‐Membered Rings: Cyclopropanes, Epoxides, Azirines and Aziridines

et al. 2023

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The activations of carbonyl compounds bearing cyclopropyl, epoxyl, azirine and aziridinyl groups by N-heterocyclic carbene (NHC) organic catalysts are reviewed. The reactions are introduced and discussed from 3 aspects according to the activation modes involved in these transformations. A brief summary on the achievements and the remaining challenges in NHC-catalyzed activation of cyclopropanes and their analogues is given at the end of this minireview. Our own perspectives on the future development within this highly active research field are also provided.

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Umpolung of donor–acceptor cyclopropanesviaN-heterocyclic carbene organic catalysis

Abstract: A carbene-catalyzed formal umpolung of Donor-Acceptor (D-A) cyclopropanes is disclosed. The cyclopropane moiety is connected to an acetyl aldehyde that can be activated by a carbene catalyst. The initially electrophilic...

Cited by 11 publications

References 69 publications

NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

Synthesis of Heterocycles from Donor-Acceptor Cyclopropanes: A Five-Year Recap

N‐Heterocyclic Carbene‐Catalyzed Activation of 3‐Membered Rings: Cyclopropanes, Epoxides, Azirines and Aziridines

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