“…A novel cinchona‐alkaloid‐derived organocatalyst has been developed to catalyze the asymmetric regioselective [3+2] cycloaddition of 3‐isothiocyanato oxindoles with dibenzylidene ketones. …”
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“…Readily available chiral ammonium salts derived from cinchona alkaloids have proven to be effective phase transfer catalysts in the asymmetric Michael reaction of 3-substituted isoindolinones. …”
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“…Endo-type cycloadducts bearing fused tetracyclic skeletons were isolated in fair yields and with high enantioselectivity (up to >99% ee) under the catalysis of modified cinchona alkaloid (DHQD)(2)PHAL. Besides, exo-type diastereomers could be produced using β-isocupreidine (β-ICD) as the catalyst, though with moderate enantioselectivity.…”
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“…The organo-catalyzed enantioselective benzylation reaction of α-trifluoromethoxy indanones afforded α-benzyl-α-trifluoromethoxy indanones with a tetrasubstituted stereogenic carbon center in excellent yield with moderate enantioselectivity (up to 57% ee). Cinchona alkaloid-based chiral phase transfer catalysts were found to be effective for this transformation, and both enantiomers of α-benzyl-α-trifluoromethoxy indanones were accessed, depended on the use of cinchonidine and cinchonine-derived catalyst. …”
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“…Developed as synthetic succedanea of cinchona alkaloids, these chiral antimalarials are currently in use as the racemate. …”
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“…[Image: see text] An operationally simple Knoevenagel condensation/asymmetric epoxidation/domino ring-opening esterification (DROE) approach has been disclosed to successfully access a good variety of (R)- and (S)-α-arylglycine esters from commercially available aldehydes, phenylsulfonyl acetonitrile, cumyl hydroperoxide, anilines, and readily available Cinchona alkaloid-based catalysts using a single solvent and reaction vessel. …”
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“…The reaction is simply catalyzed by cinchona alkaloid derivatives affording the final alkylated products in good yields and excellent enantioselectivities.…”
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“…[Image: see text] The use of a bifunctional cinchona/thiourea organocatalyst for the direct and α-stereoselective glycosylation of 2-nitrogalactals is demonstrated for the first time. …”
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“…By varying the steric and electronic surroundings of the hydrogen-bonding motif, the novel chiral Cinchona-alkaloid based selenoureas were developed. …”
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“…For this particular research work, only the most significant and relevant conformational analysis approaches have been chosen to characterize the main Cinchona alkaloid-based phase-transfer catalysts. This particular guiding study aims to rigorously compare the performance of different conformational methods, determining the strengths of each method and providing recommendations regarding suitable and efficient choices of methods for analysis.…”
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“…A methodology for the asymmetric peroxidation of γ,δ-unsaturated β-keto esters is presented. Using a cinchona-derived organocatalyst, the target δ-peroxy-β-keto esters were obtained in high enantiomeric ratios of up to 95:5. …”
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“…The 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%). …”
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“…The reactions are catalyzed by a modified cinchona alkaloid, which can function as a bifunctional, hydrogen bonding catalyst, and afford adducts in excellent yields (90–98%) and high enantioselectivities (up to 97.5:2.5 er). …”
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“…An in situ generated ortho-boronic acid containing chalcone provides the chiral benzoxaboroles via an asymmetric oxa-Michael addition of hydroxyl group attached to the boronic acid triggered by the cinchona alkaloid based chiral amino-squaramide catalysts. …”
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“…This method was exercised on a set of diastereomeric Cinchona alkaloid derivatives, where (13)C NMR data always identified the proper configuration. …”
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“…The chemistry is based on an asymmetric addition of β-ketoesters to 2-(1-alkynyl)-2-alkene-1-ones catalysed by natural cinchona alkaloids followed by a silver-catalysed intramolecular cycloisomerisation. …”
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“…The stereoselective reduction of imines with trichlorosilane catalyzed by chiral Lewis bases is a well-established procedure for the synthesis of enantio-enriched amines. Five supported cinchona-based picolinamides have been prepared and their activity tested in a model reaction. …”
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“…The reaction has been realized under nucleophilic catalysis conditions with dimeric cinchona alkaloids, providing excellent enantiocontrol of the process. …”
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“…It is well-known that most of the above-mentioned reactions are promoted by a simple aminoacid, l-proline, or, to a lesser extent, by the more complex cinchona alkaloids. However, during the past three decades, other enantiopure natural compounds, the carbohydrates, have been employed as organocatalysts. …”
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“…This enantioselective phase-transfer alkylation catalyzed by hybrid Cinchona catalysts allows for the efficient generation of the optically active products with excellent enantioselectivity, using only 1 mol% of the catalyst. …”
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