Enamides and dienamides in phosphoric acid-catalysed enantioselective cycloadditions for the synthesis of chiral amines

Varlet, Thomas; Masson, Géraldine

doi:10.1039/d1cc00590a

Cited by 31 publications

(15 citation statements)

References 278 publications

(34 reference statements)

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“…Presence of aldehyde traces in the crude reaction mixture possibly arising from the hydrolysis of intermediates ( B1/B2 ) brings support to this 2‐step mechanism. According to many precedents in phosphoric acid‐catalyzed process, and in line with a bifunctional activation mode [10,11a,20] formation of a ternary complex A involving imine 1 , dienecarbamate 2 and phosphoric acid catalyst 3 could initiate the transformation. Within the spatially defined complex A , a dual activation mode will promote a stereoselective vinylogous Mannich reaction.…”

Section: Methodsmentioning

confidence: 99%

Chiral Phosphoric Acid‐Catalyzed Enantioselective Formal [4+2] Cycloaddition Between Dienecarbamates and 2‐Benzothioazolimines

Montinho-inacio

Iorga

et al. 2022

Adv Synth Catal

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An enantioselective chiral phosphoric acid catalyzed formal [4+2] cycloaddition between 2‐benzothiazolimines and N‐H‐1,3‐dienecarbamates is described. A divergence in reaction pathways was observed depending on the dienes employed. The reaction performed with 4‐substituted dienes produced benzothiazolopyrimidines as major product in yields ranging from 42 to 67%, as single diastereoisomer and with enantioselectivity between 93 and 99%. The same reaction performed with 3‐substituted dienes, however, gave highly enantioenriched 1,2,3,4‐tetrahydroquinolines as the major products albeit with moderate diastereoselectivity.

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Section: Methodsmentioning

confidence: 99%

Chiral Phosphoric Acid‐Catalyzed Enantioselective Formal [4+2] Cycloaddition Between Dienecarbamates and 2‐Benzothioazolimines

Montinho-inacio

Iorga

et al. 2022

Adv Synth Catal

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“…In general, binaphthyl is used to synthesize chiral phosphoric acid derivatives. These catalysts have been involved in several reactions including the Diels-Alder, Nazarov, Mukaiyama Aldol, Mannich, Henry, Morita-Baylis-Hillman reactions, and 1,3-dipolar cycloadditions [146][147][148][149][150][151][152][153][154].…”

Section: Phosphoric Acidmentioning

confidence: 99%

Regiodivergent Organocatalytic Reactions

et al. 2021

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Organocatalysts are abundantly used for various transformations, particularly to obtain highly enantio- and diastereomeric pure products by controlling the stereochemistry. These applications of organocatalysts have been the topic of several reviews. Organocatalysts have emerged as one of the very essential areas of research due to their mild reaction conditions, cost-effective nature, non-toxicity, and environmentally benign approach that obviates the need for transition metal catalysts and other toxic reagents. Various types of organocatalysts including amine catalysts, Brønsted acids, and Lewis bases such as N-heterocyclic carbene (NHC) catalysts, cinchona alkaloids, 4-dimethylaminopyridine (DMAP), and hydrogen bond-donating catalysts, have gained renewed interest because of their regioselectivity. In this review, we present recent advances in regiodivergent reactions that are governed by organocatalysts. Additionally, we briefly discuss the reaction pathways of achieving regiodivergent products by changes in conditions such as solvents, additives, or the temperature.

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“…The hydroamidation is generally not compatible with a large variety of N -protecting groups; the Ritter reaction can only form secondary amides. As an alternative, several protocols involving the hydrogenation of versatile enamides 4 bearing an aryl group in the alpha position have been developed; 5 however, the preparation of the requisite starting materials may require multi-step synthesis.…”

Section: Introductionmentioning

confidence: 99%

Hydroarylation of enamides enabled by HFIP via a hexafluoroisopropyl ether as iminium reservoir

et al. 2022

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Enamides and dienamides in phosphoric acid-catalysed enantioselective cycloadditions for the synthesis of chiral amines

Abstract: Chiral substituted cyclic amines are ubiquitous among biologically active molecules and natural products and are valuable intermediates in organic synthesis. Stable and easy to synthesize enamides and dienamides are versatile...

Cited by 31 publications

References 278 publications

Chiral Phosphoric Acid‐Catalyzed Enantioselective Formal [4+2] Cycloaddition Between Dienecarbamates and 2‐Benzothioazolimines

Chiral Phosphoric Acid‐Catalyzed Enantioselective Formal [4+2] Cycloaddition Between Dienecarbamates and 2‐Benzothioazolimines

Regiodivergent Organocatalytic Reactions

Hydroarylation of enamides enabled by HFIP via a hexafluoroisopropyl ether as iminium reservoir

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