Highly Enantioselective Kinetic Resolution of Michael Adducts through N‐Heterocyclic Carbene Catalysis: An Efficient Asymmetric Route to Cyclohexenes

Chen, Xiangyu; Sun, Leilei; Liu, Qiang; Kumar, Mukesh; Peuronen, Anssi; Enders, Dieter

doi:10.1002/chem.201802420

Cited by 12 publications

(6 citation statements)

References 95 publications

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“…Based on this assumption, malononitrile derivatives, which contain two nitrile groups, attracted our attention . Although α-position derivatization reactions of malononitriles have become common, a method for α-C–O bond formation via the oxidation of malononitrile, yielding the corresponding cyanohydrin or its derivative, has not been reported. In 2016, the Hayashi group reported an oxidative amidation of α-substituted malononitriles with amines, but both nitrile groups were lost in the reaction .…”

mentioning

confidence: 87%

Preparation of O-Protected Cyanohydrins by Aerobic Oxidation of α-Substituted Malononitriles in the Presence of Diarylphosphine Oxides

et al. 2019

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A mild, reagent-cyanide-free, and efficient synthesis of O-phosphinoyl-protected cyanohydrins from readily available αsubstituted malononitriles was realized using diarylphosphine oxides in the presence of O 2 . Mechanistic studies indicated that in addition to the initial aerobic oxidation of the malononitrile derivative notable features of this process include the formation of a tetrahedral intermediate and a subsequent intramolecular rearrangement. The phosphinoyl-protecting group can be removed by alcoholysis or by reduction with DIBAL-H.

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mentioning

confidence: 87%

Preparation of O-Protected Cyanohydrins by Aerobic Oxidation of α-Substituted Malononitriles in the Presence of Diarylphosphine Oxides

et al. 2019

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“…In 2018, Enders et al investigated enantioselective kinetic resolution of racemic Michael adducts in the presence of a NHC catalyst Q (Scheme 74). [67] In this protocol, the reaction of 2-(3-oxo-1,3-diarylpropyl)malononitriles 126 as Michael adducts with α-bromoenals 1 resulted in the asymmetric synthesis of cyclohexene and recovery of Michael adduct 126' with excellent enantiopurity. This reaction proceeded through Michael addition of rac-126 to α,β-unsaturated acyl azolium from the opposite side of the NHC catalyst backbone.…”

Section: Nhc-catalyzed Synthesis Of Carbocyclesmentioning

confidence: 99%

NHC‐Catalyzed Enantioselective Transformations Involving α‐Bromoenals

Doraghi,

Ameli,

Ansariashlaghi

et al. 2024

The Chemical Record

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Abstractα‐Haloenals, especially, α‐bromoenals considered as one of the important building blocks in organic synthesis. They can participate in various (3+2)‐, (3+3)‐, (3+4)‐, and (2+4)‐annulation reactions with other organic molecules in the presence of an NHC catalyst to produce enantioenriched carbo‐, and heterocyclic compounds. Herein, we have described NHC‐catalyzed enantioselective transformations of α‐bromoenals in the synthesis of various heterocycles, and carbocycles, as well as acyclic organic compounds.

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“…A 'two flies with one swat' concept was exploited by Enders and co-workers through the blending of an aldollactonization-decarboxylation reaction and a Michael addition. 48 As depicted in Scheme 23, reaction of racemic Michael adducts with -bromoenals under chiral NHC-promotion resulted in the production of highly enantioenriched…”

Section: Syn Thesis Scheme 21 Nhc-catalyzed Dkr Of -Formyl Aryl--kementioning

confidence: 99%

Kinetic Resolution, Dynamic Kinetic Resolution and Asymmetric Desymmetrization by N-Heterocyclic Carbene Catalysis

Risi¹,

Bortolini²,

Carmine³

et al. 2019

Synthesis

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N-Heterocyclic carbenes (NHCs) are now well-established organocatalysts for a large number of asymmetric and non-asymmetric transformations. In the last 15 years, there has been significant interest in using NHCs in kinetic resolution (KR), dynamic kinetic resolution (DKR) and asymmetric desymmetrization reactions for the stereoselective synthesis of enantioenriched compounds, with diverse substrates and activation modes being adopted to this end. This short review brings into focus the progress made on NHC-catalyzed KR, DKR, and asymmetric desymmetrization from 2004 until December 2018. The literature discussed in this article is classified on the basis of the type of reaction involving the NHC catalyst.1 Introduction2 Acylation Strategies2.1 O-Acylation2.2 N-Acylation2.3 C-Acylation3 Aldol-Acylation Processes4 Benzoin Reactions5 Stetter Reactions6 Miscellaneous Approaches7 Conclusion

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Highly Enantioselective Kinetic Resolution of Michael Adducts through N‐Heterocyclic Carbene Catalysis: An Efficient Asymmetric Route to Cyclohexenes

Cited by 12 publications

References 95 publications

Preparation of O-Protected Cyanohydrins by Aerobic Oxidation of α-Substituted Malononitriles in the Presence of Diarylphosphine Oxides

Preparation of O-Protected Cyanohydrins by Aerobic Oxidation of α-Substituted Malononitriles in the Presence of Diarylphosphine Oxides

NHC‐Catalyzed Enantioselective Transformations Involving α‐Bromoenals

Kinetic Resolution, Dynamic Kinetic Resolution and Asymmetric Desymmetrization by N-Heterocyclic Carbene Catalysis

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