5682-83-7Relevant articles and documents
Molecular mechanism of micellar catalysis of cross aldol reaction: Effect of surfactant chain length and surfactant concentration
Vashishtha, Manu,Mishra, Manish,Undre, Sachin,Singh, Man,Shah, Dinesh O.
, p. 143 - 154 (2015)
The importance of alkyl chain length and concentration of quaternary ammonium surfactants (QAS) in the micellar catalysis of cross aldol reaction was investigated. The NaOH-micellar system catalyzed aldol reaction of benzaldehyde and cyclohexanone to α,α′-dibenzylidene cyclohexanone (di condensation/desired product) over mono condensation product was used as model reaction for this study. The C16QAS micellar system (QAS with n-hexadecyl group) gave highest cyclohexanone conversion (90%) to desired product (82%) showing that C16QAS micellar system possesses optimum properties and/or microenvironment for this reaction. Furthermore, the micellar system with high surfactant concentration (C16QAS; >150mM) made the reaction faster giving >99% conversion to selectively desired product (>99%) within 30min The large interface created by C16QAS micelles in the aqueous medium at high surfactant concentration makes the reaction faster by facilitating the interaction of hydrophobic reactants and water soluble catalyst (OH- ions). The activation of benzaldehyde molecules, their localization preferably near the interface and stabilization of enolate ions (reactive intermediates) by micellar system at high surfactant concentration were observed to be promoting the cross reaction selectively to the desired product.
Redox-Neutral Cobalt(III)-Catalyzed C-H Activation/Annulation of α,β-Unsaturated Oxime Ether with Alkyne: One-Step Access to Multisubstituted Pyridine
Mohanty, Smruti Ranjan,Pati, Bedadyuti Vedvyas,Banjare, Shyam Kumar,Das Adhikari, Gopal Krushna,Ravikumar, Ponneri Chandrababu
, p. 1074 - 1083 (2021/01/14)
A redox neutral Co(III)-catalyzed annulation of α,β-unsaturated oxime ether with alkyne has been reported. Multisubstituted pyridines were synthesized in good yields without the use of any heavy metal oxidants. The developed methodology tolerates a variety of functional groups. Notably, this transformation has been applied to the late-stage modification of the bioactive molecule dehydropregnenolone.
Valmet Chiral Schiff-Base Ligands And Their Copper(II) Complexes as Organo, Homogeneous and Heterogeneous Catalysts for Henry, Cyanosilylation and Aldol Coupling Reactions
Arora, Zinnia,Eftemie, Diana-Ioana,Spinciu, Adela,Maxim, C?t?lin,Hanganu, Ana-Maria,Tudorache, Madalina,Cojocaru, Bogdan,Pavel, Octavian D.,Granger, Pascal,Andruh, Marius,Parvulescu, Vasile I.
, p. 4634 - 4644 (2021/09/08)
Cyanosilylation, aldol coupling and asymmetric Henry reactions were carried out with L- and D-valmet ligands in different configurations: i) coordinated to sodium ions, as organocatalysts, with week base properties, ii) complexes with copper(II), as homogeneous catalysts, and iii) immobilized copper(II) complexes onto graphene oxide (GO) as heterogeneous catalysts. For the reaction of benzaldehyde and nitromethane in water these afforded an asymmetric Henry reaction, with a spectacular increase of the conversion and ee (92.5 and 95.8 %, respectively) after the deposition on GO. Ligand complexed copper was also effective for cyanosilylation and Aldol coupling reaction.
