<i>trans</i>-1,2-Diaminocyclohexane-based sulfonamides as effective hydrogen-bonding organocatalysts for asymmetric Michael–hemiacetalization reaction

Dajek, Maciej; Kowalczyk, Rafał; Boratyński, Przemysław J.

doi:10.1039/c8cy01199k

Cited by 18 publications

(15 citation statements)

References 32 publications

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“…[11] We also proved that simple sulfonamides with single hydrogen-bond donating center could offer very high stereoselectivities with less than 1 mol% loading. [12] However, application of the same reaction conditions for the most effective sulfonamide C2 provided a mixture of adduct forms (epimeric hemiacetals and open chain) with only 89% ee for the reaction of 5-phenyl-1,3-cyclohexanedione (1 b) (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Cinchona Squaramide‐Catalyzed Intermolecular Desymmetrization of 1,3‐Diketones Leading to Chiral 1,4‐Dihydropyridines

et al. 2020

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Addition of prochiral cyclic 1,3‐diketones to Michael acceptors applying bifunctional Cinchona‐derived squaramides resulted in chiral adducts with stereoselectivities of up to 99% ee and allowed for desymmetrization of the nucleophile. These labile hemiacetal intermediates were transformed to new 1,4‐dihydropyridines with high diastereoselectivities and no erosion of optical purity. Their further oxidation to pyridine followed by Fisher indolization provided chiral pyridine‐indoles.

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Section: Resultsmentioning

confidence: 99%

Cinchona Squaramide‐Catalyzed Intermolecular Desymmetrization of 1,3‐Diketones Leading to Chiral 1,4‐Dihydropyridines

et al. 2020

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“…The ‘primary–tertiary’ amines 1 (i.e., compounds ( R , R )- 1a , ( R , R )- 1b , ( S , S )- 1b, ( R , R )- 1c , and ( R , R )- 1d ) were prepared from the respective, enantiopure diastereomers of trans -1,2-diaminocyclohexane ( trans -DACH), according to the literature procedure [12]. α-Hydroxyiminoketones 5 were prepared by nitrozation of ethyl methyl ketone in the case of 7a [38] and by oximation of dibenzoyl in the case of 7b [39] based on the published procedures.…”

Section: Methodsmentioning

confidence: 99%

“… trans -1,2-diaminocyclohexane (DACH) and its ‘desymmetrized’ derivatives 1 (Reproduced with permission from [12]).…”

Section: Schemes and Tablementioning

confidence: 99%

“…In recent years, much attention has been paid to so-called bifunctional catalysts, which are prepared by modifications of the amino groups. Derivatives of type 1 with a cyclic amine motif are promising building blocks for the synthesis of new bifunctional catalysts [11,12] and are important synthons for the preparation of some bioactive compounds [13,14,15,16,17]. An efficient method for the ‘desymmetrization’ of DACH, reported only in recent years, comprises two-fold N , N -alkylation of only one NH 2 group using α,ω-dihaloalkylating reagents as shown in Scheme 1 [12].…”

Section: Introductionmentioning

confidence: 99%

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2-Unsubstituted Imidazole N-Oxides as Novel Precursors of Chiral 3-Alkoxyimidazol-2-ylidenes Derived from trans-1,2-Diaminocyclohexane and Other Chiral Amino Compounds

et al. 2019

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‘Desymmetrization’ of trans-1,2-diaminocyclohexane by treatment with α,ω-dihalogenated alkylation reagents leads to mono-NH2 derivatives (‘primary-tertiary diamines’). Upon reaction with formaldehyde, these products formed monomeric formaldimines. Subsequently, reactions of the formaldimines with α-hydroxyiminoketones led to the corresponding 2-unsubstituted imidazole N-oxide derivatives, which were used here as new substrates for the in situ generation of chiral imidazol-2-ylidenes. Upon O-selective benzylation, new chiral imidazolium salts were obtained, which were deprotonated by treatment with triethylamine in the presence of elemental sulfur. Under these conditions, the intermediate imidazol-2-ylidenes were trapped by elemental sulfur, yielding the corresponding chiral non-enolizable imidazole-2-thiones in good yields. Analogous reaction sequences, starting with imidazole N-oxides derived from enantiopure primary amines, amino alcohols, and amino acids, leading to the corresponding 3-alkoxyimidazole-2-thiones were also studied.

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“…To date, bifunctional organocatalysts which contains sulfonamide and a basic amine moiety have attracted remarkable attention of organic chemists due to its numerous synthetic applications 21 .…”

Section: Introductionmentioning

confidence: 99%

Nickel Nanoparticles Immobilized on a Porous Triazine-Thiourea-Sulfonamide as an Efficient Heterogeneous Catalyst for Reduction of Carbonyl Compounds

Rahimi

Ghorbani‐Vaghei

Alavinia

2021

Preprint

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In order to investigate the role of silica template, polymers and nickel nanoparticles on the reduction of aldehydes/ketones, a novel porous triazine-thiourea-sulfonamide polymeric organic support (TTSA) was prepared via in-situ polymerization of melamine (1,3,5-triazine-2,4,6-triamine), thiourea and benzene-1,3-disulfonyl chloride in the presence of silica nanoparticles as a template led to the synthesize silica TTSA nanocomposite. Next, after removal of the template, the nanocomposite was transformed into mesoporous poly triazine-thiourea-sulfonamide. Ni nanoparticles (Ni NPs) were then decorated on the designed mesoporous polymer support and the resulting TTSA@Ni NPs nanospheres were employed as heterogeneous catalyst in the construction of alchohols from reduction of aldehydes/ketones using formic acid/triethyl amine as a reducing agent in water as solvent. The catalyst is low-cost, non-toxic, and can be reused for several catalytic cycles without decreasing the activity.

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trans-1,2-Diaminocyclohexane-based sulfonamides as effective hydrogen-bonding organocatalysts for asymmetric Michael–hemiacetalization reaction

Abstract: Simple sulfonamide organocatalysts deliver unparalleled efficiency in the asymmetric Michael–hemiacetalization cascade.

Cited by 18 publications

References 32 publications

Cinchona Squaramide‐Catalyzed Intermolecular Desymmetrization of 1,3‐Diketones Leading to Chiral 1,4‐Dihydropyridines

Cinchona Squaramide‐Catalyzed Intermolecular Desymmetrization of 1,3‐Diketones Leading to Chiral 1,4‐Dihydropyridines

2-Unsubstituted Imidazole N-Oxides as Novel Precursors of Chiral 3-Alkoxyimidazol-2-ylidenes Derived from trans-1,2-Diaminocyclohexane and Other Chiral Amino Compounds

Nickel Nanoparticles Immobilized on a Porous Triazine-Thiourea-Sulfonamide as an Efficient Heterogeneous Catalyst for Reduction of Carbonyl Compounds

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