• Employing a nucleophilic catalyst, such as a tertiary amine and phosphine, this reaction provides a densely functionalized product (e.g. functionalized allyl alcohol in the case of aldehyde as the electrophile). (wikipedia.org)
  • In connection with our ongoing project that deals with the catalytic potential of the cinchona-alkaloid-derived amides,[17-19] we became interested in examining the reaction of allenoates with imines in the presence of a chiral tertiary amine catalyst. (docme.ru)
  • 2 ) through their use of a cinchona alkaloid-derived primary amine catalyst. (pnas.org)
  • By synthesizing conformationally rigid cinchona alkaloid derivatives, they were able to elucidate a stereochemical model for the desymmetrization, which enabled their development of an improved cinchona-based catalyst that is accessible through a shortened two-step synthesis from menthol. (pnas.org)
  • With an easily accessible cinchona alkaloid catalyst, efficient enantioselective peroxidation and epoxidation have been successfully developed. (organic-chemistry.org)
  • Molecular assembly of an achiral phosphine and a chiral primary amine: a highly efficient supramolecular catalyst for the enantioselective Michael reaction of aldehydes with maleimides. (edu.sa)
  • Cinchona alkaloid-lewis acid catalyst systems for enantioselective ketene-aldehyde cycloadditions. (edu.sa)
  • Since a relative short period (about 50 years) chemist have also used these alkaloids as chiral catalyst for a wide variety of asymmetric transformations. (worldwidescience.org)
  • As shown in Scheme 1 , enzymatic control of whether guanidinium enolate 1 undergoes an intramolecular conjugate addition or a protonation dictates whether 1 is an intermediate for the biosynthesis of polycyclic guanidine alkaloids ptilocaulin or batzelladine K. In this paper, we wish to describe the development of a small-molecule catalyst system to achieve high stereoselectivity and control of chemoselectivity of two different reaction intermediates. (pnas.org)
  • 52. Xi-Tao Li, Qiang-Shuai Gu, Xiao-Yang Dong, Xiang Meng, and Xin-Yuan Liu*, "Cinchona Alkaloid‐Based Sulfonamide/Copper Catalyst for Asymmetric Radical Oxytrifluoromethylation of Alkenyl Oximes. (sustech.edu.cn)
  • This catalyst system also enables the coupling of secondary phosphines with aryl halides. (organic-chemistry.org)
  • a] The reaction was carried out in THF at 20 8C for 1 h with 4 a (2 equiv) in the presence of the catalyst generated from [{RhCl(C2H4)2}2] and a chiral phosphine ligand. (docme.ru)
  • Cinchona Alkaloid Amide Catalyzed Enantioselective Formal [2+2]Cycloadditions of Allenoates and Imines Synthesis of 2 4-Disubstituted Azetidines. (docme.ru)
  • 3.4 Chiral ferrocenyl imino phosphines as ligands for palladium catalysed enantioselective allylic alkylations (Pierluigi Barbaro, Claudio Bianchini, Giuliano Giambastiani and Antonio Togni). (nhbs.com)
  • The enantioselective extraction of aqueous 3,5-dinitrobenzoyl-R,S-leucine (A(R,S)) by a cinchona alkaloid extractant (C) in 1,2-dichloroethane was studied at room temperature (294 K) in a batch system for a range of intake concentrations (10(-4)-10(-3) mol/L) and pH values (3.8-6.6). (worldwidescience.org)
  • Chua, P. J. Process for highly enantioselective Michael addition of 1,3-diaryl-1,3-propanedione to nitroolefins using using cinchona alkaloids as recyclable organocatalysts. (sustc.edu.cn)
  • Barbas III, C.F. J. Core-Structure-Motivated Design of a Phosphine-Catalyzed [3+2] Cycloaddition Reaction: Enantioselective Syntheses of Spirocyclopenteneoxindoles. (sustc.edu.cn)
  • Asymmetric synthesis of chiral aldehydes by conjugate additions with bifunctional organocatalysis by cinchona alkaloids. (edu.sa)
  • Wynberg's report from 1977 that natural cinchona alkaloids catalyze the asymmetric conjugate addition of aromatic thiols to cycloalkenones is a landmark discovery in hydrogen bonding organocatalysis. (hammersmithendocrinology.org)
  • The new model rationalizes the stereoselective outcome of Wynberg's reaction and provides a new, general model for asymmetric cinchona organocatalysis. (hammersmithendocrinology.org)
  • 2.3 Asymmetric phase transfer catalysed alkylation of glycine imines using cinchona alkaloid derived quaternary ammonium salts (Barry Lygo and Benjamin I. Andrews). (nhbs.com)
  • This article reviews the applications of cinchona alkaloids as asymmetric catalysts. (worldwidescience.org)
  • Reactions between conjugated 5-phenylpenta-2,4-dienoic acids and phenol gave 3-alkylidenedihydrobenzofuran alkaloid motifs while biologically active 7-arylbenzofuran derivatives were prepared by starting from 2-phenylphenols. (diva-portal.org)
  • Additionally, these studies have identified the use of phosphine oxides (e.g. triphenylphosphine oxide) as useful ligands for palladium-catalyzed cross-coupling reactions. (worldcat.org)
  • In addition, nucleophilic amines such as DMAP and DBU as well as phosphines have been found to successfully catalyze this reaction. (wikipedia.org)
  • 1,3-Dipolar cycloaddition and palladium(II)-catalyzed alkoxycarbonylation were leveraged for the construction of the hexacyclic scaffold en route to both natural products. (hammersmithendocrinology.org)
  • The use of these barks in medicines against "fevers" in Europe in the 17th century made the exploitation of cinchonas of Peru a highly productive process, and those cinchona trees became menaced. (worldwidescience.org)
  • Note that only part of the chiral phosphine ligand is shown for the sake of clarity. (wikipedia.org)
  • Chapter 7 describes the development of an effective grinding device for the grinding of herbal samples such as Cinchona barks. (worldwidescience.org)