Reaction of an open-chain analogue of reissert compound hydrofluoroborate salt with ethyl acrylate. A reinvestigation

Perrin, Sandrine; Monnier, K.; Laude, B.; Kubicki, Marek M.; Blacque, Olivier

doi:10.1016/s0040-4039(98)00029-x

Cited by 6 publications

(2 citation statements)

References 4 publications

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“…While the reason for this is not immediately clear, enantioselectivity remained excellent. Arylacetic acids containing para-, meta-and orthotolyl substituents were all incorporated in high yields and excellent stereoselectivities (23)(24)(25), demonstrating that orthosubstitution has no detrimental effect on the course of the reaction, unlike in our previous synthesis of dihydropyridinones 9 amongst other examples. 7,12a,12c paraPhenyl as well as 1-and 2-naphthyl substitution gave the desired dihydropyridinones (26-28) in moderate yields, although stereoselectivities remained excellent.…”

Section: Exploration Of the Acetic Acid Nucleophile Scopementioning

confidence: 74%

Exploring the scope of the isothiourea-mediated synthesis of dihydropyridinones

et al. 2015

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The exploration and expansion of the scope of the isothiourea-mediated synthesis of dihydropyridinones is presented. The use of ketimines derived from α,β-unsaturated γ-ketoesters as the Michael acceptor in a Michael addition / lactamisation cascade gives access to a range of dihydropyridinones with high enantioselectivity. The nature of the N-sulfonyl group present on the ketimine is extensively investigated, with further studies into derivatisation of the dihydropyridinone core also reported. IntroductionThe direct organocatalytic asymmetric functionalisation of readily available, bench-stable carboxylic acids 1 towards valueadded products has received much attention since the seminal report by Romo and co-workers in 2001 on the intramolecular nucleophile-catalysed aldol / lactonisation (NCAL) reaction (Scheme 1). 2 Further work from the Romo group has demonstrated the utility of ammonium and isothiouronium enolates generated from carboxylic acids in the stereoselective synthesis of β-lactones, 3 including the application to the total synthesis of (+)-omphadiol 3j 1 and (−)-curcumalactone 2 (Scheme 1), amongst others. 3l Scheme 1 Romo and co-wokers' intramolecular NCAL reaction 2 and select examples of natural products accessed using this reaction. 3j,3lWe have previously explored the scope of the intramolecular reactions of ammonium and isothiouronium enolates, 4 allowing access to dihydrobenzofurans, 5 2H-indenes, 5a THFs, 5b as well as pyrrolidines. Our previous synthesis of dihydropyridinones reacted isothiouronium enolates generated from carboxylic acids with N-tosyl chalcone-derived ketimines in a Michael addition / lactamisation cascade (Scheme 2a). 9 This afforded a range of dihydropyridinones in high yields and excellent stereoselectivity. In this methodology the N-tosyl substituent was employed exclusively in the ketimine Michael acceptor. Furthermore, the use of chalcones as the backbone of the ketimine, alongside the requirement for aryl or heteroaryl acetic acids, resulted in dihydropyridinones furnished with three (hetero)aryl substituents thereby constraining the scope of the hetercyclic products. To extend these studies, alternative ketimine backbones incorporating more versatile functional handles, whilst maintaining the reactivity of the Michael acceptor were explored. Herein we report the successful incorporation of ketimines derived from α,β-unsaturated γ-ketoesters within this ARTICLE Journal Name 2 | J. Name., 2012, 00, 1-3 This journal is © The Royal Society of Chemistry 2012Scheme 2 Organocatalytic synthesis of dihydropyridinones methodology, 10,13 affording dihydropyridinone products containing ester substituents as functional handles (Scheme 2b). Extensive exploration of the sulfonyl substituent and the potential for derivatisation of the dihydropyridinone core is also described. Results and Discussion OptimisationInitial studies showed that α,β-unsaturated γ-ketimine ester 6 was a competent electrophile for intermolecular Michael addition / lactamisation with the isothiouronium en...

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Section: Exploration Of the Acetic Acid Nucleophile Scopementioning

confidence: 74%

Exploring the scope of the isothiourea-mediated synthesis of dihydropyridinones

et al. 2015

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“…[1][2][3][4][5][6][7][8][9] Therefore there are numerous known methods for their synthesis [10][11] and new procedures are continually being developed. [12][13][14][15][16][17] Our previous studies 29,30 on the reactivity of an open-chain analogue of Reissert compound hydrofluoroborate salt 1aA (Ar 1 = Ar 2 = Ph) with ethyl acrylate have led us to the synthesis of ethyl 3,6-diphenyl-2-1H-pyridone-4-carboxylate 6aAE (Ar 1 = Ar 2 = Ph, R = Et) (Scheme 1). The structural advantage and the convenient synthetic method of this compound led us to look for the generalisation of this procedure and we report here a more complete study of the scope of the process.…”

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confidence: 99%

A Münchnonimine-based Method for the Synthesis of 3,6-diaryl-2(1H)-pyridones

Burger¹,

Monnier-Jobé²,

Perrin

et al. 2002

Journal of Chemical Research

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Reactions of the Hydrofluoroborate Salts of Open-Chain Analogues of Reissert Compounds with Some α,β-Ethylenic Esters

Perrin

Monnier²,

Laude

et al. 1999

Eur. J. Org. Chem.

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The reaction of the hydrofluoroborate salt of an open‐chain analogue of a Reissert compound with some α,β‐ethylenic esters does not give a [4 + 2] cycloadduct, as previously described in the case of ethyl acrylate. The reaction starts with a 1,3‐dipolar cycloaddition of a münchnone imine 5c, d. The [3 + 2] cycloadducts 13 evolve via a rearrangement–condensation sequence to give a substituted 2‐pyridone derivative 18 or 19. The proposed mechanism has been verified by the isolation and structural X‐ray analysis of some compounds of the reaction sequence.

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Reaction of an open-chain analogue of reissert compound hydrofluoroborate salt with ethyl acrylate. A reinvestigation

Cited by 6 publications

References 4 publications

Exploring the scope of the isothiourea-mediated synthesis of dihydropyridinones

Exploring the scope of the isothiourea-mediated synthesis of dihydropyridinones

A Münchnonimine-based Method for the Synthesis of 3,6-diaryl-2(1H)-pyridones

Reactions of the Hydrofluoroborate Salts of Open-Chain Analogues of Reissert Compounds with Some α,β-Ethylenic Esters

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