L-proline derivatives based on a calix[4]arene scaffold as chiral organocatalysts for the direct asymmetric aldol reaction in water

Aktas, Mehmet; Uyanik, Arzu; Eymür, Serkan

doi:10.1080/10610278.2015.1073288

Cited by 15 publications

(12 citation statements)

References 15 publications

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“…Subsequently, a series of new asymmetric aldol catalytic system of aqueous phase reaction was developed, particularly, proline‐docked glucoside catalyst showed high yield and the moderate ee value . In 2015, Aktas et al . further designed and synthesized a new series of water‐compatible proline catalysts for aldol reactions with high yields (up to 82%), good enantioselectivities (ee up to 81%) and high diastereoselectivities (dr up to 91:9).…”

Section: Introductionmentioning

confidence: 99%

Stability of Immobilization of Bipyridine‐proline on Zn‐Modified Bimodal Mesoporous Silicas and Recyclable Catalytic Performance in Asymmetric Aldol Reaction

et al. 2019

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The organic-inorganic mesoporous materials (ZZnBMMs) were successfully synthesized by Zn-grafting into the surface of bimodal mesoporous silicas (BMMs) via covalent bond, and then immobilization of (2 S,2'S)-N,N'-([2,2'-bipyridine]-3,3'-diyl) bis(pyrrolidine-2-carboxamide) (Z) onto the Zn-modified BMMs through coordination method. The influences of washed parameters such as various solvents (petroleum ether, CH 2 Cl 2 , CH 3 OH, or DMSO) and pretreated temperature on the structural stability of obtained ZZnBMMs were investigated thoroughly, which were extensively characterized by means of XRD patterns, UV-vis and FT-IR spectra, N 2 sorption isotherms, SEM images, and SAXS patterns. The results showed that petroleum ether could be acted as optimum solvent for washing ZZnBMMs when pre-treated temperature was around 20°C. The SAXS patterns evidently demonstrated that ZZnBMMs before and after washing presented the fractal features, suggesting their surface roughness and structural irregularities, in which, the mass fractal (D m ) values were gradually decreased along with not only the increased polarity of used solvents (petroleum ether, CH 2 Cl 2 , CH 3 OH, and DMSO), but also enhanced washing temperature of from 20-60°C and prolonged time of from 4-168 hrs. Furthermore, the ZZnBMMs as a heterogeneous catalyst for asymmetric aldol reaction exhibited the recycled (at least 6 times) catalytic performances with high efficiency (around 92.1% yield) and good selectivity (up to 68% ee).

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Section: Introductionmentioning

confidence: 99%

Stability of Immobilization of Bipyridine‐proline on Zn‐Modified Bimodal Mesoporous Silicas and Recyclable Catalytic Performance in Asymmetric Aldol Reaction

et al. 2019

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“…In this context, calixarenes are ideal supramolecular macrocyclic scaffolds for the design of molecular receptors and organocatalysts due to their unique and tunable molecular architecture together with the ease of functionalization on the lower and upper rims [24–28]. Interestingly, their hydrophobic cavity also exhibits phase transfer catalytic function [29].…”

Section: Introductionmentioning

confidence: 99%

“…Compared with the lower rim in the cone conformation of calixarenes, the functionalization of the upper rim is more challenging. Notably, it should be more valuable to exploit the cavity of upper rim-functionalized calixarenes because of the possibility of simultaneously using the hydrophobic cavity and chiral sites during a catalytic process [24–25]. …”

Section: Introductionmentioning

confidence: 99%

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

Tong

Chen

et al. 2018

Beilstein J. Org. Chem.

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A number of upper rim-functionalized calix[4]thiourea cyclohexanediamine derivatives have been designed, synthesized and used as catalysts for enantioselective Michael addition reactions between nitroolefins and acetylacetone. The optimal catalyst 2 with a mono-thiourea group exhibited good performance in the presence of water/toluene (v/v = 1:2). Under the optimal reaction conditions, high yields of up to 99% and moderate to good enantioselectivities up to 94% ee were achieved. Detailed experiments clearly showed that the upper rim-functionalized hydrophobic calixarene scaffold played an important role in cooperation with the catalytic center to the good reactivities and enantioselectivities.

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“…Among the virtually countless examples available in recent literature, L-proline-modified CAs constitute an interesting subject of study [19–32]. Proline-based systems in general have been proven excellent stereoselective organocatalysts [33–40]. In particular, CA derivatives bearing proline units (on both the upper and the lower rim) have been tested as catalysts for asymmetric aldol reactions in water [28–30 33].…”

Section: Introductionmentioning

confidence: 99%

“…Proline-based systems in general have been proven excellent stereoselective organocatalysts [33–40]. In particular, CA derivatives bearing proline units (on both the upper and the lower rim) have been tested as catalysts for asymmetric aldol reactions in water [28–30 33]. Similar derivatives have also been studied as hydrogelators [22–23].…”

Section: Introductionmentioning

confidence: 99%

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

Russo¹,

Meo²

2017

Beilstein J. Org. Chem.

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Polarimetry was used to investigate the binding abilities of a chiral calix[4]resorcinarene derivative, bearing L-proline subunits, towards a set of suitably selected organic guests. The simultaneous formation of 1:1 and 2:1 host–guest inclusion complexes was observed in several cases, depending on both the charge status of the host and the structure of the guest. Thus, the use of the polarimetric method was thoroughly revisited, in order to keep into account the occurrence of multiple equilibria. Our data indicate that the stability of the host–guest complexes is affected by an interplay between Coulomb interactions, π–π interactions, desolvation effects and entropy-unfavorable conformational dynamic restraints. Polarimetry is confirmed as a very useful and versatile tool for the investigation of supramolecular interactions with chiral hosts, even in complex systems involving multiple equilibria.

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L-proline derivatives based on a calix[4]arene scaffold as chiral organocatalysts for the direct asymmetric aldol reaction in water

Cited by 15 publications

References 15 publications

Stability of Immobilization of Bipyridine‐proline on Zn‐Modified Bimodal Mesoporous Silicas and Recyclable Catalytic Performance in Asymmetric Aldol Reaction

Stability of Immobilization of Bipyridine‐proline on Zn‐Modified Bimodal Mesoporous Silicas and Recyclable Catalytic Performance in Asymmetric Aldol Reaction

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

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