Catalytic Generation of Donor‐Acceptor Cyclopropanes under <i>N</i>‐Heterocyclic Carbene Activation and their Stereoselective Reaction with Alkylideneoxindoles

Prieto, Liher; Sánchez-Díez, Eduardo; Uria, Uxue; Reyes, Efraím; Carrillo, Luisa; Vicario, José L.

doi:10.1002/adsc.201700198

Cited by 48 publications

(21 citation statements)

References 99 publications

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“…According to the best of our knowledge, only two other enantioselective organocatalytic reactions have been presented. One is a NHC‐catalyzed (NHC=N‐heterocyclic carbene) activation of a formyl‐substituted acceptor cyclopropane, thus trapping the ring‐opening of the in situ formed D‐A cyclopropane in an hetero [4+2] cycloaddition reaction, while the other is an enantioselective synthesis of 1,3‐dichlorides by an electrophilic activation of formyl‐substituted meso ‐cyclopropanes …”

Section: Methodsmentioning

confidence: 99%

Directing the Activation of Donor–Acceptor Cyclopropanes Towards Stereoselective 1,3‐Dipolar Cycloaddition Reactions by Brønsted Base Catalysis

et al. 2017

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The first stereoselective organocatalyzed [3+ +2] cycloaddition reaction of donor-acceptor cyclopropanes is presented. It is demonstrated that by applying an optically active bifunctional Brønsted base catalyst, racemic di-cyano cyclopropylketones can be activated to undergo as tereoselective 1,3-dipolar reaction with mono-and polysubstituted nitroolefins.The reaction affords functionalizedcyclopentanes with three consecutive stereocenters in high yield and stereoselectivity.Based on the stereochemical outcome,amechanism in which the organocatalyst activates both the donor-acceptor cyclopropane and nitroolefin is proposed. Finally,c hemoselective transformations of the cycloaddition products are demonstrated.

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Section: Methodsmentioning

confidence: 99%

Directing the Activation of Donor–Acceptor Cyclopropanes Towards Stereoselective 1,3‐Dipolar Cycloaddition Reactions by Brønsted Base Catalysis

et al. 2017

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“…14a Later, Vicario and co-workers also applied the same concept to cleave donor–acceptor cyclopropanes by NHC catalysis to design a formal [4+2] cycloaddition using 3-alkenyloxindoles and β-oxo-γ,δ-unsaturated esters as heterodienes. 14b α,β-Unsaturated aldehyde 53 is able to generate homoenolate 55 on reacting with the NHC catalyst generated from ent - A1 . This homoenolate, upon protonation, is converted into enolate 56 , which is successfully trapped by the enone to accomplish the synthesis of optically active cis -configured dihydropyranone derivatives (Scheme 9b ).…”

Section: Catalysis Through Covalent Activationmentioning

confidence: 99%

Organocatalyzed Oxa-Diels–Alder Reactions: Recent Progress

et al. 2021

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Oxa-Diels-Alder reaction is a straightforward, atom-economical process for the construction of six membered oxa-cycle which is a privileged structure due to its omnipresence in several pharmaceuticals and natural products. Like many other asymmetric transformations, organocatalysis provides an elegant pathway to their synthesis via [4+2] annulation under mild reaction conditions. The oxa-Diels reactions either utilize α,β-unsaturated carbonyl as oxadiene with a suitable dienophile or simple carbonyl as dienophile with other dienes. A range of organocatalysts have been explored in the past decade to execute this strategy. The catalysts induce stereoselectivities via two basic reactivities: 1) Formation of chiral intermediates, 2) Selectively activating suitable reactants in transition state. The present review assembles organocatalyzed asymmetric oxa-Diels-Alder reactions published in last ten years’ time span with detailed discussion on mechanistic approaches.

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“…Chiral N‐heterocyclic carbenes catalytically generate DACs by interaction with formylcyclopropanes 77 incorporating two electron‐withdrawing groups at the three‐membered ring, and the resulting intermediate undergoes formal [4+2] cycloaddition with a suitable substrate such as the alkylideneoxindole 78 . The overall process results in the enantio‐ and diastereoselective synthesis of tetrahydropyrano[2,3‐ b ]indoles 79 (Scheme ).…”

Section: Synthesis Of Five‐membered Nitrogen Heterocyclesmentioning

confidence: 99%

Donor–Acceptor Cyclopropanes as an Expedient Building Block Towards the Construction of Nitrogen‐Containing Molecules: An Update

et al. 2020

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Nitrogen‐containing molecules are the key structural constituent of many pharmaceutical compounds that play a pivotal role in drug development. Owing to their multifaceted medicinal importance, several synthetic approaches have been delineated in the recent past for their construction. Over the past few decades the augmented use of donor–acceptor cyclopropanes (DACs) as three‐carbon synthetic equivalents, despite their ring strain, for the construction of innumerable hetero‐ and carbocycles of pharmaceutical importance has raised the interest of synthetic chemists to this topic. Owing to their zwitterionic nature due to the vicinal disposition of donor and acceptor groups, they have been frequently used in ring‐opening reactions, cycloadditions, and rearrangements. This review is mainly focused on assorted reactions of DACs with various nitrogen‐containing dipolarophiles like imines, azides, cyanates, isothiocyanates, nitrosocarbonyls, hydrazines, diaziridines, triazinanes, diazenes, etc. towards the synthesis of nitrogen‐containing molecules of pharmaceutical and industrial importance. This review is in continuation of our review published in the Israel Journal of Chemistry in April 2016, and includes the literature from April 2016 to May 2019.

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Catalytic Generation of Donor‐Acceptor Cyclopropanes under N‐Heterocyclic Carbene Activation and their Stereoselective Reaction with Alkylideneoxindoles

Cited by 48 publications

References 99 publications

Directing the Activation of Donor–Acceptor Cyclopropanes Towards Stereoselective 1,3‐Dipolar Cycloaddition Reactions by Brønsted Base Catalysis

Directing the Activation of Donor–Acceptor Cyclopropanes Towards Stereoselective 1,3‐Dipolar Cycloaddition Reactions by Brønsted Base Catalysis

Organocatalyzed Oxa-Diels–Alder Reactions: Recent Progress

Donor–Acceptor Cyclopropanes as an Expedient Building Block Towards the Construction of Nitrogen‐Containing Molecules: An Update

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