Enantioselective Synthesis of 4‐Isoxazolines by 1,3‐Dipolar Cycloadditions of Nitrones to Alkynals Catalyzed by Fluorodiphenylmethylpyrrolidines

Alemán, José V.; Fraile, Alberto; Marzo, Leyre; Ruano, José Luis Garcı́a; Llorente, Cristina; Díaz‐Tendero, Sergio

doi:10.1002/adsc.201200033

Cited by 48 publications

(17 citation statements)

References 41 publications

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“…On the basis of our experimental results and previous literature,12a–d we have proposed a plausible mechanism to account for the observed stereoselectivity of the reaction in Scheme . Initially, the highly reactive iminium intermediate 5 , generated from the diphenyl prolinol O ‐trimethylsilyl ( O ‐TMS) ether catalyst I and phenylpropionaldehyde ( 2 a ), undergoes nucleophilic attack from the nitrogen of methyl 2‐(tosylamino)phenyl α,β‐unsaturated ketone 1 l to generate the ketene intermediate 6 .…”

Section: Methodssupporting

confidence: 68%

Asymmetric One‐Pot Synthesis of 1,4‐Dihydroquinolines via an Organocatalytic Aza‐Michael/Michael Cascade Strategy

Lee¹,

Heo²,

Kim³

2015

Adv Synth Catal

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As ynthetic method for the construction of fully substituted enantioenriched 1,4-dihydroquinolines using an organocatalytic aza-Michael/Michael cascade reaction has been developed. The asymmetric reactiono f2 -(tosylamino)phenyl a,bunsaturated ketones with alkynyl aldehydes, promoted by diphenylprolinol O-TMS ether as an organocatalyst, generated chiral 1,4-dihydroquinolines in good to high yields with excellent enantioselectivities (up to 97 % ee).

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Section: Methodssupporting

confidence: 68%

Asymmetric One‐Pot Synthesis of 1,4‐Dihydroquinolines via an Organocatalytic Aza‐Michael/Michael Cascade Strategy

Lee¹,

Heo²,

Kim³

2015

Adv Synth Catal

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“…A similar organocatalytic analogue of this reaction was published independently by Alemán, Fraile et al . In this case, ( S )‐2‐fluorodiphenylmethylpyrrolidine was found to be the best catalyst among the tested chiral secondary amines.…”

Section: Isoxazolines (Dihydroisoxazoles)supporting

confidence: 64%

Synthesis of Diheteroatomic Five‐Membered Heterocyclic Compounds from α,β‐Unsaturated Aldehydes

Keiko

Вчисло

2016

Asian J Org Chem

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The recent increasei ni nterest in the chemistry of azoles has been owing to their paramount importance in several essential fields of research, such as pharmacology, medicine, biology, the organic synthesis of fine chemicals, agriculturalc hemistry, and the chemical industry.T his Focus Review summarizes and highlights recently developed methods for the synthesis of five-membered N,N-, N,O-, andN ,Sheterocycles based on the transformations of 2-alkenals. Over the last 15 years, these reactions, which often differ from reactions involving other a,b-unsaturatedc arbonyl compoundsi nt erms of methoda nd results, have gathered significant momentum. The multitude of catalytic and tech-nological novelties discussed in this Focus Review,s uch as asymmetricm etal-and organocatalysis,o ne-pot multicomponent reactions that proceed through domino, cascade, or tandem sequences, and microwave activation,p romote the formation of ad iverse range of target products, the structures of which becomec lear from the mechanistic schemes given in this Focus Review.T he mechanisms discussed reflect great advances in the chemo-, regio-, and stereoselectivity of the reactions of 2-alkenals, which allows new azoles and related compounds (imidazoles, pyrazoles, oxazoles, thiazoles, and their hydrogenatedd erivatives) to be synthesized.[a] Prof.The ORCID identification number(s) for the author(s) of this articlecan be found under http://dx.Scheme2.One-potsynthesis of imidazoles 8 and tentativemechanism of the reaction.T s= 4-toluenesulfonyl, TMS = tert-butyltrimethylsilyl, Bn = benzyl, Lg = leaving group.Scheme3.Enantioselective synthesiso f3-hydroxyalkyl and 3-aminoalkyli midazo[1,2-a]pyridines (9)through an asymmetricorganocatalytic [3+ +2] annulation strategy.Alk = alkyl.Scheme4.One-potsynthesis of imidazole-containingc ondensed heterocycles by the reaction of 2-alkoxypropenalswith N-binucleophiles.Scheme9.Aroute to 2-(1'-alkoxyvinyl)imidazolidines 27 through the condensation of alkoxy propenals.

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“…10 In this sense, Alem an, Fraile and co-workers described a 1,3-dipolar reaction between nitrones 19 and alkynals 9 catalyzed by (S)-2-(fluorodiphenylmethyl)pyrrolidine (10b) to give 4-isoxazolines (2,3-dihydroisoxazoles) 20 with high ee's, excellent yields, and low catalyst loading (1e5 mol %) (Scheme 8). 11 The catalytic loading could be reduced to 1 mol % with only a slight increase in the reaction time. The reaction allowed the incorporation of different substituents at R 1 and R 2 , but the reaction with alkyl derivatives at these positions did not work.…”

Section: Alkynals Under Iminium Catalysismentioning

confidence: 99%

Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

et al. 2014

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Enantioselective Synthesis of 4‐Isoxazolines by 1,3‐Dipolar Cycloadditions of Nitrones to Alkynals Catalyzed by Fluorodiphenylmethylpyrrolidines

Cited by 48 publications

References 41 publications

Asymmetric One‐Pot Synthesis of 1,4‐Dihydroquinolines via an Organocatalytic Aza‐Michael/Michael Cascade Strategy

Asymmetric One‐Pot Synthesis of 1,4‐Dihydroquinolines via an Organocatalytic Aza‐Michael/Michael Cascade Strategy

Synthesis of Diheteroatomic Five‐Membered Heterocyclic Compounds from α,β‐Unsaturated Aldehydes

Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

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