Highly enantioselective [3+2] coupling of cyclic enamides with quinone monoimines promoted by a chiral phosphoric acid

Zhang, Minmin; Shibata, Yu; Hu, Fangzhi; Liao, Yijun; Liao, Lixin; Xu, Xiao‐Ying; Yuan, Wei‐Cheng; Zhang, Xiaomei

doi:10.1039/c6cc01200k

Cited by 32 publications

(12 citation statements)

References 38 publications

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“…Indanones 1 (R = Me, t ‐Bu, F, Cl) were prepared by a method similar to that in the literature (Figure 2). [ 11–13 ] Friedel‐Crafts acylation of substituted benzenes with 3‐chloropropanoyl chloride with AlCl 3 , followed by intramolecular Friedel‐Crafts alkylation of the resulting chloroketones, provided indanones 1 in 21%–75% yields.…”

Section: Resultsmentioning

confidence: 99%

Brønsted acid‐catalyzed aldol cyclotrimerization of 1‐indanones in ionic liquid: An experimental and DFT study of substituent effect

Okazaki

Aoyama

Kitagawa

2020

J of Physical Organic Chem

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Reactions of 5‐R‐1‐indanones (R = Me, t‐Bu, Cl, F) in ionic liquids in the presence of Brønsted acid afforded substituted truxenes as aldol cyclotrimerization products, whose yields were found to be better in [BMIM][Tf2N] than in [BMIM][BF4]. Their cyclotrimerizations were slower and gave lower yields than that of the parent 1‐indanone. Furthermore, the reaction mixtures contained some amounts of intermediate products, 5‐R‐2‐(5‐R‐1‐indanylidene)‐1‐indanone, formed by the initial aldol condensation. These results suggested that both the electron‐donating and the electron‐withdrawing substituents at the C(5) position reduced the rate of cyclotrimerization. This rate retardation was supported by DFT/B3LYP calculations with the PCM solvation model. The activation energies of the reaction of the protonated indanones and the indenols in the initial aldol condensation were increased by both the electron‐donating group (EDG) and the electron‐withdrawing group (EWG). The transition states in the second aldol condensation and in the electron‐cyclization were also destabilized by both the EDG and the EWG.

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Section: Resultsmentioning

confidence: 99%

Brønsted acid‐catalyzed aldol cyclotrimerization of 1‐indanones in ionic liquid: An experimental and DFT study of substituent effect

Okazaki

Aoyama

Kitagawa

2020

J of Physical Organic Chem

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“…In the past few years, the research of reactions of quinone derivatives have attracted more and more interest and impressive progress has been made ,. Our group has also been working on developing of new transformations of quinone derivatives –…”

Section: Methodsmentioning

confidence: 99%

Unprecedented Tandem Conjugate Addition/C‐O Ester Migration of α‐Cyano Arylacetates with a Quinone Monoimine

et al. 2019

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An unprecedented conjugate addition/CÀ O ester migration of α-cyano arylacetates with a quinone monoamine was presented, which allowed for the synthesis of various 2,2-diarylacetonitriles in moderate to quantitative yields. This method is applicable to a series of α-cyano arylacetates with different aryl groups. Moreover, in order to demonstrate the synthetic utility of this transformation, 2-(cyano(phenyl))-4-(4-methylphenylsulfonamido)ethyl carbonate was subjected in hydrogenation to generate a 2,2-diarylethylcarbamate.Quinone derivatives are highly electrophilic and can react with many nucleophilic reagents. In the past few years, the research of reactions of quinone derivatives have attracted more and more interest and impressive progress has been made. [1,2] Our group has also been working on developing of new transformations of quinone derivatives. [2p-r] α-Substituted α-cyano acetates are good nucleophiles and have been widely used in the construction of densely functionalized compounds. [3.4] However, up to now, there is only one report about reaction of α-cyano acetates with quinone derivatives. Chandra and co-workers recently reported an organocatalytic asymmetric conjugate addition/cyclization of p-quinone diimides with α-cyano acetates, which afforded various cyclic imidines in good yields with moderate to good enantioselectivities (Scheme 1, a). [2c] As a part of our ongoing exploration of new transformations involving quinone derivatives, we also studied the reaction of α-cyano arylacetates with a quinone monoimine. To our surprise, an unprecedented tandem conjugate addition/CÀ O ester migration occurred and a kind of novel 2,2-diarylacetonitriles were obtained in moderate to quantitative yields (Scheme 1, b). CÀ O ester migration of α-nitro acetates has been reported previously. [5] However, to the best of our knowledge, up to now, there is no report about CÀ O ester migration of α-cyano acetates. Therefore, this is the first time that CÀ O ester migration of α-cyano acetates was presented.First, we initiated the reaction of ethyl á-cyano phenylacetate 1 a with quinone monoimine 2 a in acetonitrile at room temperature. The reaction provided the product 3 a with moderate yield in 18 hours (Table 1, entry 1). The structure of [a] Dr.

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“…(3 + 2) cycloaddition is one of the most convergent methods for the synthesis of five-membered heterocycles fused with aromatic rings . More specifically, (3 + 2) formal cycloaddition of quinones (or quinone monoimines) with electron-rich alkenes affords a convenient synthesis of dihydrofurans, the oxygen analogues of indolines. ,, The aza variant of this reaction using quinone diimides to produce indolines has not been well-explored. Furthermore, in these examples, there are few methods to synthesize 2,3-disubstituted indolines. , Indeed, while the chemistry of quinone diimides is rich, their unfriendly preparation (often relying on lead tetraacetate), their sensitivity toward hydrolysis of the carbon–nitrogen double bond, and their redox properties leading to self-rearomatization or oxidative coupling hamper their wide use .…”

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confidence: 99%

Chiral Phosphoric Acid-Catalyzed Enantioselective Construction of 2,3-Disubstituted Indolines

Gelis

Bouchet

et al. 2021

Org. Lett.

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Highly enantio-and regioselective selective (3 + 2) formal cycloaddition of b-substituted ene-and thioenecarbamates as well as cyclic enamides with quinone diimides catalyzed by a BINOL-and SPINOL-derived phosphoric acid has been reported. A wide variety of 2-amino 2,3-disubtituted indolines, including polycyclic ones, were prepared in generally high yields (up to 98%) with moderate to complete diastereoselectivities and in most cases excellent enantioselectivities (up to 99% ee).Chiral 2,3-disubstituted indolines are privileged heterocyclic rings frequently encountered in various natural bioactive alkaloids (such as (-)-physostigmine, (+)-aspidospermidine and pircrinine, Figure 1) 1 and biologically active drugs (such as pentopril and relcovaptan). 2 In addition, they have been successfully employed as chiral auxiliaries and organocatalysts in asymmetric synthesis. 3 As a result, several asymmetric catalytic approaches have been established for the construction of indoline rings. 4 Despite these elegant achievements, the development of novel asymmetric synthetic routes of 2,3disubstituted indolines is still highly desirable.

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Highly enantioselective [3+2] coupling of cyclic enamides with quinone monoimines promoted by a chiral phosphoric acid

Cited by 32 publications

References 38 publications

Brønsted acid‐catalyzed aldol cyclotrimerization of 1‐indanones in ionic liquid: An experimental and DFT study of substituent effect

Brønsted acid‐catalyzed aldol cyclotrimerization of 1‐indanones in ionic liquid: An experimental and DFT study of substituent effect

Unprecedented Tandem Conjugate Addition/C‐O Ester Migration of α‐Cyano Arylacetates with a Quinone Monoimine

Chiral Phosphoric Acid-Catalyzed Enantioselective Construction of 2,3-Disubstituted Indolines

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