852913-53-2Relevant academic research and scientific papers
Synthesis of novel crown ether-squaramides and their application as phase-transfer catalysts
Bagi, Péter,Bakó, Péter,Drahos, László,Fehér, Zsuzsanna,Huszthy, Péter,Kupai, József,Nagy, Sándor,Rapi, Zsolt,Richter, Dóra,Simon, András
, (2021/11/08)
This work presents the synthesis of six new phase-transfer organocatalysts in which the squaramide unit is directly linked to the nitrogen atom of an aza-crown ether. Four chiral skeletons, namely hydroquinine, quinine, cinchonine (cinchonas), and α-D-glu
New enantiopure binaphthyl-cinchona thiosquaramides: synthesis and application for enantioselective organocatalysis
Nagy, Sándor,Dargó, Gyula,Kisszékelyi, Péter,Fehér, Zsuzsanna,Simon, András,Barabás, Júlia,H?ltzl, Tibor,Mátrav?lgyi, Béla,Kárpáti, Levente,Drahos, László,Huszthy, Péter,Kupai, József
, p. 5948 - 5959 (2019/04/17)
This work presents the first successful applications of cinchona-thiosquaramides in asymmetric reactions. Binaphthyl-cinchona squaramides and thiosquaramides were synthesised, and then used as organocatalysts to promote the catalytic enantioselective Mich
Catalytic Enantio- and Diastereoselective Mannich Addition of TosMIC to Ketimines
Franchino, Allegra,Chapman, Jack,Funes-Ardoiz, Ignacio,Paton, Robert S.,Dixon, Darren J.
, p. 17660 - 17664 (2018/11/10)
Chiral amines bearing a stereocenter in the α position are ubiquitous compounds with many applications in the pharmaceutical and agrochemical sectors, as well as in catalysis. Catalytic asymmetric Mannich additions represent a valuable method to access such compounds in enantioenriched form. This work reports the first enantio- and diastereoselective addition of commercially available p-toluenesulfonylmethyl isocyanide (TosMIC) to ketimines, affording 2-imidazolines bearing two contiguous stereocenters, one of which is fully-substituted, with high yields and excellent stereocontrol. The reaction, catalyzed by silver oxide and a dihydroquinine-derived N,P-ligand, is broad in scope, operationally simple, and scalable. Derivatization of the products provides enantioenriched vicinal diamines, precursors to NHC ligands and sp3-rich heterocyclic scaffolds. Computations are used to understand catalysis and rationalize stereoselectivity.
D-Mannitol-derived novel chiral thioureas: Synthesis and application in asymmetric Henry reactions
Liu, Miaoxi,Ji, Nan,Wang, Li,Liu, Peng,He, Wei
supporting information, p. 999 - 1004 (2018/02/23)
Five novel thioureas have been obtained through multi-step reactions from D-Mannitol as starting material and applied as catalysts in the asymmetric Henry reaction. Using catalyst 7a, (1S,2R)-2-nitro-1-phenylpropan-1-ol containing two chiral centers was o
ASYMMETRIC SYNTHESIS OF FUNAPIDE
-
Page/Page column 39; 55; 56, (2018/01/20)
This invention is directed to asymmetric synthesis of funapide, which is useful for the treatment and/or prevention of sodium channel-mediated diseases or conditions, such as pain.
Plant Process for the Preparation of Cinchona Alkaloid-Based Thiourea Catalysts
Wang, Yi,Milkiewicz, Karen L.,Kaufman, Mildred L.,He, Linli,Landmesser, Nelson G.,Levy, Daniel V.,Allwein, Shawn P.,Christie, Michael A.,Olsen, Mark A.,Neville, Christopher J.,Muthukumaran, Kannan
, p. 408 - 413 (2017/03/24)
Cinchona alkaloid-based thiourea catalysts (1a and 1b) belong to an important class of bifunctional organocatalysts, which has been widely used for a variety of asymmetric reactions. The commercial availability of these catalysts is sporadic, and limited
Novel chiral Schiff base/Ti(IV) catalysts for the catalytic asymmetric epoxidation of: N -alkenyl sulfonamides
Ji, Nan,Yuan, Jiani,Liu, Miaoxi,Lan, Ting,He, Wei
supporting information, p. 7731 - 7734 (2016/07/06)
A new method has been developed for the catalytic asymmetric epoxidation of N-alkenyl sulfonamides in the presence of a Schiff base derived from hydroquinine and Ti(Oi-Pr)4. This reaction proceeds under mild conditions, providing facile access to chiral epoxy sulfonamides in good yields (up to 95%) with excellent enantioselectivities (up to 97% ee).
Direct catalytic enantio- and diastereoselective ketone aldol reactions of isocyanoacetates
De La Campa, Raquel,Ortín, Irene,Dixon, Darren J.
supporting information, p. 4895 - 4898 (2015/04/14)
A catalytic asymmetric aldol addition/cyclization reaction of unactivated ketones with isocyanoacetate pronucleophiles has been developed. A quinine-derived aminophosphine precatalyst and silver oxide were found to be an effective binary catalyst system and promoted the reaction to afford chiral oxazolines possessing a fully substituted stereocenter with good diastereoselectivities and excellent enantioselectivities.
Highly enantioselective phosphination and hydrophosphonylation of azomethine imines: Using chiral squaramide as a hydrogen bonding organocatalyst
Kong, Ling-Pei,Li, Nai-Kai,Zhang, Shao-Yun,Chen, Xiang,Zhao, Min,Zhang, Ya-Fei,Wang, Xing-Wang
supporting information, p. 8656 - 8670 (2014/12/10)
Enantioselective phosphination and hydrophosphonylation reactions between azomethine imines and diarylphosphine oxides or dialkyl phosphites were respectively developed by the use of a chiral squaramide as the hydrogen bonding organocatalyst, which afforded two types of phosphorus containing product in high yields with good to excellent enantioselectivities.
Cinchona alkaloid derivatives, their process of preparation and their use as catalysts
-
Paragraph 0096-0099, (2014/02/15)
The present invention provides a process for preparing a substantially stereochemically pure compound of formula (I), or a salt thereof wherein R1 and R2 are independently selected from the group consisting of H, -CH2-CH3, and -CH=CH2, the process comprising the step of demethylating the corresponding methylated compound of formula (II) in the presence of an alkaline or alkaline earth metal (C1-C10) alkylthiolate salt and a polar aprotic solvent.
