1210360-60-3Relevant academic research and scientific papers
Self-assembled fibrillar networks of a multifaceted chiral squaramide: Supramolecular multistimuli-responsive alcogels
Schiller, Jana,Alegre-Requena, Juan V.,Marqués-López, Eugenia,Herrera, Raquel P.,Casanovas, Jordi,Alemán, Carlos,Díaz Díaz, David
, p. 4361 - 4374 (2016)
Chiral N,N′-disubstituted squaramide 1 has been found to undergo self-assembly in a variety of alcoholic solvents at low concentrations leading to the formation of novel nanostructured supramolecular alcogels. The gels responded to thermal, mechanical, op
Catalytic asymmetric construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements
Qu, Jingping,Wang, Baomin,Wang, Wenyao,Wei, Shiqiang,Zhang, Wande
, p. 6550 - 6553 (2021/07/07)
An organocatalytic asymmetric process was reported for the sterically precise construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements. A series of interesting products featuring the union of a centrally chiral pyrazolone moiety and an axially chiral styrene unit were obtained in high yield with excellent diastereoselectivity and enantioselectivity (up to 99% ee, >20?:?1 dr). The process has the characteristics of mild reaction conditions, simple operation and broad substrate scope. The result of gram-scale reaction indicates that the reaction has good practicability.
Enantioselective Synthesis of Cyclohexenol Derivatives from ?-Aryl-Substituted Enals via an Organocatalyzed Three-Component Reaction
Majee, Debashis,Jakkampudi, Satish,Arman, Hadi D.,Zhao, John C.-G.
, p. 9166 - 9170 (2019/11/14)
A three-component reaction between ?-aryl-substituted α,β-unsaturated aldehydes and nitroalkenes was realized by using cinchona alkaloid-derived (thio)ureas and squaramides via the dienolate intermediates. This unprecedented 1,3- A nd 1,5-reactivity of dienolates of the ?-aryl-α,β-unsaturated aldehydes led to the formation of cyclohexenol derivatives with four contiguous stereogenic centers and a chiral substituent at C2 with good diastereoselectivities and high ee values. Such reactivities of the dienolates are totally different from those of the corresponding dienamine intermediates.
Catalytic Asymmetric Synthesis of Quaternary Barbituric Acids
Del Pozo, Sandra,Vera, Silvia,Oiarbide, Mikel,Palomo, Claudio
, p. 15308 - 15311 (2017/11/06)
The catalytic asymmetric α-functionalization of prochiral barbituric acids, a subtype of pseudosymmetric 1,3-diamides, to yield the corresponding 5,5-disubstituted (quaternary) derivatives remains essentially unsolved. In this study 2-alkylthio-4,6-dioxopirimidines are designed as key 1,3-diamide surrogates that perform exceedingly in amine-squaramide catalyzed C-C bond forming reactions with vinyl ketones or Morita-Baylis-Hillmann-type allyl bromides as electrophiles. Mild acid hydrolysis of adducts affords barbituric acid derivatives with an in-ring quaternary carbon in unprecedented enantioselectivity, offering valuable materials for biological evaluations.
Total Syntheses of Pyroclavine, Festuclavine, Lysergol, and Isolysergol via a Catalytic Asymmetric Nitro-Michael Reaction
Bhunia, Subhajit,Chaudhuri, Saikat,Bisai, Alakesh
supporting information, p. 11234 - 11238 (2017/08/26)
A catalytic enantioselective construction of vicinal stereocenters is reported. The reaction takes advantage of thiourea-catalyzed intramolecular nitronate addition onto α,β-unsaturated ester to afford exceptional levels of enantioselectivity (up to 97 % ee) with moderate diastereoselectivity (up to 4:1). Using this method, a cross-conjugated ester was synthesized in few steps, from which a 6-endo-trig cyclisation led to the formation of all required functionalities for total syntheses of ergot alkaloids. The strategy not only offers first total syntheses of ergot alkaloids, festuclavine (1 c), and pyroclavine (1 e), and but also an efficient and general approach to other congeners such as, lysergol (1 b), and isolysergol (1 d).
Organocatalytic enantio- and diastereoselective conjugate addition to nitroolefins: When ketoamides surpass ketoesters
Du, Haiying,Rodriguez, Jean,Bugaut, Xavier,Constantieux, Thierry
supporting information, p. 8458 - 8466 (2014/07/08)
Our findings on the bifunctional squaramide-catalyzed enantioselective conjugate addition of ketoamides to nitroolefins are disclosed. It appears that simple acyclic methylene ketoamides, unlike the extensively studied ketoesters, afford the products in excellent diastereoselectivities, and maintain high yields and enantioselectivities. Moreover, competition and kinetic studies were conducted to rationalize the observed reactivity and selectivity. The high level of diastereocontrol, along with the amenability of the amide group to postfunctionalization, dramatically increase the synthetic usefulness of the transformation.
First example of quinine-squaramide catalyzed enantioselective addition of diphenyl phosphite to ketimines derived from isatins
George, Jimil,Sridhar,Reddy, B.V. Subba
supporting information, p. 1595 - 1602 (2014/03/21)
A highly enantioselective addition of diphenyl phosphite to ketimines derived from isatins has been achieved using a bifunctional organocatalyst, quinine-derived squaramide catalyst. This method works efficiently with several ketimines to produce the corresponding 3-amino-2-oxoindolin-3-yl-phosphonates in excellent yields with high enantioselectivity (up to 98% ee). This journal is The Royal Society of Chemistry 2014.
