Bimorpholine-Mediated Enantioselective Intramolecular and Intermolecular Aldol Condensation

Kanger, Tõnis; Kriis, Kadri; Laars, Marju; Kailas, Tiiu; Müürisepp, Aleksander-Mati; Pehk, Tõnis; Lopp, Margus

doi:10.1021/jo070524i

Cited by 61 publications

(27 citation statements)

References 39 publications

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“…As a part of our ongoing studies in organocatalysis [16–19] we investigated the organocatalytic approach to the asymmetric desymmetrization of the title compounds with malonates. Three types of organocatalysts providing noncovalent interactions were used for this purpose: Cinchona alkaloids ( I – V ), thiourea derivatives ( VI , VII ) and squaramide derivatives ( VIII , IX ) (Fig.…”

Section: Resultsmentioning

confidence: 99%

Organocatalytic asymmetric addition of malonates to unsaturated 1,4-diketones

Žari¹,

Kailas²,

Kudrjashova³

et al. 2012

Beilstein J. Org. Chem.

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SummaryThe organocatalytic Michael addition of malonates to symmetric unsaturated 1,4-diketones catalyzed by thiourea and squaramide derivatives with Cinchona alkaloids afforded the formation of a new C–C bond in high yields (up to 98%) and enantiomeric purities (up to 93%). The absolute configuration of the product was suggested from comparison of the experimental and calculated VCD spectra of the reaction product 3a.

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Section: Resultsmentioning

confidence: 99%

Organocatalytic asymmetric addition of malonates to unsaturated 1,4-diketones

Žari¹,

Kailas²,

Kudrjashova³

et al. 2012

Beilstein J. Org. Chem.

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“…In light of these considerations, Kanger et al investigated the use of different mono salts of bimorpholines for the synthesis of (S)-1 and (S)-2, starting from the assumption that their reactivity may be similar to proline, due to their structural similarity [65,66]. Indeed, both compounds are cyclic secondary amines with the chiral centre at the α-position of the nitrogen atom, with an acidic proton at a distance of four chemical bonds from the nucleophilic nitrogen.…”

Section: Other Amino Acidsmentioning

confidence: 99%

Organocatalyst Design for the Stereoselective Annulation towards Bicyclic Diketones and Analogues

et al. 2022

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The Wieland–Miescher ketone, Hajos–Parrish–Eder–Sauer–Wiechert ketone, and their analogues are bicyclic diketones essential as building blocks for the synthesis of several natural and bioactive molecules. For this reason, since 1971, when Hajos and Parrish and Eder, Sauer, and Wiechert reported the stereoselective synthesis of these compounds promoted by L-proline, numerous methodologies and organocatalysts have been studied over the years with the aim of identifying increasingly efficient asymmetrical syntheses of these bicyclic ketones. This review will outline the methodological and stereochemical features of the organocatalytic stereoselective synthesis of these bicyclic scaffolds based on the different organocatalysts employed from 1971 until today. Particular emphasis will be given to the structural features of the catalysts and to the reaction conditions.

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“…Organocatalysts from other chiral sources for the syntheses of Wieland-Miescher ketone (1). [16][17][18][19][20][21][22][23][24][25][26] Scheme 2. Synthetic study of (±)-aristomakine (30).…”

Section: Figurementioning

confidence: 99%

“…32 Reduction of Wieland-Miescher ketone (1) followed by protection as tertbutyldimethylsilyl (TBS) ether and subsequent bromination provided bromide 46. Subsequent radical bromination with nbromosuccinimide at C-6 followed by dehydrobromination provided 4-bromo-4,6-dienone, which was introduced a formyl equivalent by palladium catalyzed coupling with an oxygenated stannane 47 33 [16][17][18][19][20][21][22][23][24][25][26] Scheme 2. Synthetic study of (±)-aristomakine (30).…”

mentioning

confidence: 99%