Bifunctional Organocatalysts for Enantioselective aza-Morita−Baylis−Hillman Reaction

Matsui, Katsuya; Takizawa, Shinobu; Sasai, Hiroaki

doi:10.1021/ja0500254

Cited by 268 publications

(61 citation statements)

References 27 publications

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“…12 Using a specifically designed ionic liquid with a chiral anion, enantioselectivities of up to 84% ee were obtained in the aza-Baylis-Hillman reaction. These results are comparable with the values obtained with the best catalysts for the enantioselective aza-Baylis-Hillman reaction in conventional solvents (94% ee, 13 83% ee 14 ). These results indicate that the key to effective chirality transfer lies in strong intermolecular interactions such as electrostatic attraction and hydrogen bonding between the solvent molecules and the intermediates or the transition states of the enantioselective reaction step.…”

Section: Introductionsupporting

confidence: 87%

Synthesis of novel room temperature chiral ionic liquids: application as reaction media for the heck arylation of aza-endocyclic acrylates

Pastre¹,

Génisson²,

Saffon³

et al. 2010

J. Braz. Chem. Soc.

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Novos líquidos iônicos aquirais e quirais foram preparados utilizando-se rotas sintéticas inéditas e/ou otimizadas. Estas séries de líquidos iônicos do tipo imidazolínico, imidazólico e piridínico foram totalmente caracterizadas, incluindo-se análises por calorimetria diferencial de varredura (DSC). O desempenho desses líquidos iônicos (LIs) foi demonstrado empregando-se a arilação de Heck de aza-acrilato endocíclicos com sais de arenodiazônio ou iodetos de arila. As arilações de Heck realizadas na presença destas entidades iônicas quirais, seja como um solvente ou um aditivo, foram eficazes levando à completa conversão do substrato, em bons a excelentes rendimentos do aduto de Heck na maioria dos casos, apesar de não ser observada indução assimétrica em nenhum dos casos estudados. Dois novos complexos quirais de paládio do tipo carbeno N-heterocíclico foram preparados em bons rendimentos a partir de um sal imidazólico quiral e suas estruturas caracterizadas por difração de raios-X. De modo geral, a arilação de Heck empregando tetrafluoroboratos de arenodiazônio em líquidos iônicos demonstrou ser mais eficiente do que os protocolos tradicionais em termos de reatividade e rendimentos de reação.New achiral and chiral RTILs were prepared using novel and/or optimized synthetic routes. These new series of imidazolinium, imidazolium, pyridinium and nicotine-derived ionic liquids were fully characterized including differential scanning calorimetry (DSC) analysis. The performance of these achiral and chiral room temperature ionic liquids (RTILs) was demonstrated by means of the Heck arylation of endocyclic acrylates employing arenediazonium salts and aryl iodides. The Heck arylations performed in the presence of these ionic entities, either as a solvent or as an additive, were effective leading to complete conversion of the substrate and good to excellent yield of the Heck adduct. In spite of the good performances, no asymmetric induction was observed in any of the cases studied. Two new diastereoisomeric NHC-palladium complexes were prepared in good yields from a chiral imidazolium salt and their structure characterized by X-ray diffraction. Overall, the Heck arylations employing arenediazonium tetrafluoroborates in RTILs were more effective than the traditional protocols employing aryl iodides in terms of reactivity and yields.

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Section: Introductionsupporting

confidence: 87%

Synthesis of novel room temperature chiral ionic liquids: application as reaction media for the heck arylation of aza-endocyclic acrylates

Pastre¹,

Génisson²,

Saffon³

et al. 2010

J. Braz. Chem. Soc.

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“…Sasai et al reported an aza-Morita-Baylis-Hillman reaction catalyzed by the bifunctional organocatalyst 16 (Scheme 29). [50] The pyridyl moiety plays as the role of a Lewis base unit and the diol moiety acts as a Brønsted acid site. [51] Interestingly, only the 3-pyridylaminomethyl moiety at the 3-position turned out to be quite effective with respect to both enantioselectivity and reactivity.…”

Section: Binol Derivativesmentioning

confidence: 99%

Recent Progress in Chiral Brønsted Acid Catalysis

Akiyama¹,

Itoh²,

Fuchibe³

2006

Adv Synth Catal

881

183

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“…Recently, hydrogen-bond donors such as ureas/thioureas, [10][11][12][13][14][15][16][17][18][19][20][21][22][23] BINOL/diols, [24][25][26][27][28][29][30][31][32] and phosphoric acids [33][34][35][36][37][38][39][40] have been also recognized as efficient organocatalysts. Novel urea and thiourea derivatives were developed as organocatalysts and their potential as a general acid has been successfully demonstrated by several groups.…”

Section: Introductionmentioning

confidence: 99%

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

2010

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We have developed several multifunctional thiourea catalysts bearing a tertiary amine or an 1,2-amino alcohol in expectation of their synchronous activation of a nucleophile and an electrophile through both acid-base and hydrogen-bonding interactions. From these studies, it was revealed that the weak acidity of thioureas compared with metallic Lewis acids could be overcome by this modification. The bifunctional aminothiourea could be used efficiently for a wide range of diastereoselective and enantioselective nucleophilic reactions such as Michael addition of 1,3-dicarbonyl compounds to nitroolefines, aza-Henry reaction of nitroalkanes to N-Boc imines, and hydrazination of cyclic b b-keto esters. We also discovered that multifunctional thiourea catalyst, bearing an 1,2-amino alcohol moiety, significantly accelerated the Petasis-type reaction of alkenylboronic acids to Nphenoxycarbonyl quinolinium salts, prepared from quinolines and phenyl chloroformate, to afford 1,2-addition products with high enantioselectivity (up to 97% ee). Furthermore, to expand the synthetic applicability of the thiourea-catalyzed asymmetric reactions, tandem organocatalyzed reactions were explored to establish the concise one-pot synthesis of chiral densely functionalized three-, five-, and six-membered compounds.

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Bifunctional Organocatalysts for Enantioselective aza-Morita−Baylis−Hillman Reaction

Cited by 268 publications

References 27 publications

Synthesis of novel room temperature chiral ionic liquids: application as reaction media for the heck arylation of aza-endocyclic acrylates

Synthesis of novel room temperature chiral ionic liquids: application as reaction media for the heck arylation of aza-endocyclic acrylates

Recent Progress in Chiral Brønsted Acid Catalysis

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

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