22975-21-9Relevant academic research and scientific papers
Optically active helical polymers with pendent thiourea groups: Chiral organocatalyst for asymmetric michael addition reaction
Zhang, Haiyang,Yang, Wantai,Deng, Jianping
, p. 1816 - 1823 (2015)
This article reports a novel category of helical substituted polyacetylenes bearing pendant thiourea groups and showing remarkable asymmetric catalysis ability. Thiourea-based monomer and another chiral monomer underwent copolymerization, affording copoly
Axially chiral guanidine as enantioselective base catalyst for 1,4-addition reaction of 1,3-dicarbonyl compounds with conjugated nitroalkenes
Terada, Masahiro,Ube, Hitoshi,Yaguchi, Yusuke
, p. 1454 - 1455 (2006)
A new strategy for designing chiral guanidine molecules is presented, which features the introduction of an axially chiral binaphthyl backbone. The axially chiral guanidine catalysts thus developed facilitated the highly enantioselective 1,4-addition reac
Ni(II)-bis[(R,R)-N,N′-dibenzylcyclohexane-1,2-diamine]Br2 catalyzed enantioselective Michael additions of 1,3-dicarbonyl compounds to conjugated nitroalkenes
Evans, David A.,Seidel, Daniel
, p. 9958 - 9959 (2005)
A highly enantioselective Michael addition of 1,3-dicarbonyl compounds to nitroalkenes has been developed that employs a newly developed Ni(II)-(bis)diamine based catalyst. The reaction scope includes substituted and unsubstituted malonates, β-ketoesters,
Tandem Ring Opening/Cyclization of trans-2-Aryl-3-nitrocyclopropane-1,1-dicarboxylates with 2-Aminopyridines: Access to Pyrido[1,2-a]pyrimidin-4-one Derivatives
Selvi, Subramani,Srinivasan, Kannupal
, p. 5644 - 5648 (2017)
A tandem ring-opening/cyclization reaction of trans-2-aryl-3-nitrocyclopropane-1,1-dicarboxylates with 2-aminopyridines was discovered. The reaction did not require the assistance of any catalyst and proceeded more efficiently in water than in organic solvents. This strategy afforded pyrido[1,2-a]pyrimidin-4-one derivatives having a carboxylate group at C3 in 62–90 % yields.
Study on the Catalytic Behavior of Bifunctional Hydrogen-Bonding Catalysts Guided by Free Energy Relationship Analysis of Steric Parameters
Yang, Chen,Wang, Jie,Liu, Yang,Ni, Xiang,Li, Xin,Cheng, Jin-Pei
, p. 5488 - 5497 (2017)
Free energy relationship (FER) studies to correlate steric parameters with the enantiocatalytic performance of bifunctional tertiary-amine hydrogen-bonding catalysts, including (S,S)-cyclohexane-1,2-diamine-derived thioureas, Cinchona alkaloid derived thioureas, and (S,S)-cyclohexane-1,2-diamine-derived squaramides, in Michael reactions revealed that the reactions are much favored by catalysts with less bulky N-substituents. The observed FERs are independent of the chiral scaffold and hydrogen-bond donor, and deepen the understanding of current bifunctional hydrogen-bonding catalysts. Moreover, DFT calculations were performed to interpret the observed high reactivities of thioureas with less bulky substituents. In particular, the computations demonstrated the advantage of a benzyl thiourea catalyst, in which an extra CH???π interaction between catalyst and substrate is the key factor.
Reaction of ω-nitrostyrene with diethyl malonate in the presence of chiral nickel(II) complexes
Reznikov,Klimochkin
, (2012)
Single-ligand complexes of nickel(II) with chiral diamines based on L-proline and (S)-camphor efficiently catalyze addition of diethyl malonate to ω-nitrostyrene in the presence of 1 equiv of triethylamine as co-catalyst. The reaction enantioselectivity d
Efficient Tertiary Amine/Weak Acid Bifunctional Mesoporous Silica Catalysts for Michael Addition Reactions
Das, Sayantani,Goswami, Anandarup,Murali, Nagarajan,Asefa, Tewodros
, p. 910 - 919 (2013)
We describe the development and application of efficient bifunctional acid-base mesoporous silica catalysts, denoted hereafter as Ext-SBA-15-NMe2, comprising tertiary amine and silanol (weak acid) groups for the Michael addition reaction. The c
High-Pressure-Mediated Thiourea-Organocatalyzed Asymmetric Michael Addition to (Hetero)aromatic Nitroolefins: Prediction of Reaction Parameters by PCP-SAFT Modelling
Bittorf, Lukas,Held, Christoph,Knierbein, Michael,Reiser, Oliver,Sadowski, Gabriele,Siewert, Riko,Verevkin, Sergey P.,Weinbender, Thomas
, p. 1292 - 1296 (2020)
Thiourea-organocatalyzed Michael additions of diethyl malonate to various heteroaromatic nitroolefins (13 examples) have been studied under high-pressure (up to 800 MPa) and ambient pressure conditions. High pressure was conducive to enhanced product yields by a factor of 2–12 at a given reaction time, high reaction rates (reaction times were decreased from 72–24 h down to 4–24 h) and high enantioselectivity. Elucidating the effects of solvents for maximizing reaction rates and yields has been carried out using the Perturbed-Chain Polar Statistical Associating Fluid Theory (PCP-SAFT), allowing for the first time a prediction of the kinetic profiles under high-hydrostatic-pressure conditions.
Enantioselective Michael Reaction of Malonates to Nitroolefins Catalyzed by Bifunctional Organocatalysts
Okino, Tomotaka,Hoashi, Yasutaka,Takemoto, Yoshiji
, p. 12672 - 12673 (2003)
Michael reaction of malonates to nitroolefins with chiral bifunctional organocatalysts, bearing both a thiourea and tertiary amino group, afforded Michael adducts with high yields and enantioselectivities (up to 95%, up to 93% ee). Copyright
Enantioselective addition of diethyl malonate to ω-nitrostyrenes in the presence of cobalt and manganese complexes with N,N′-dibenzyl-(1S,2S)- cyclohexane-1,2-diamine
Reznikov,Golovin,Klimochkin
, (2012)
Enantioselective addition of diethyl malonate to nitrostyrene and para-chloronitrostyrene is catalyzed by cobalt and manganese complexes with N,N′-dibenzyl-(1S,2S)-cyclohexane-1,2-diamine generated in situ. Enantiomeric excess of the (R)-isomers in the re
