1540-34-7Relevant articles and documents
Synthesis and Thermal Behavior of Heteroleptic γ-Substituted Acetylacetonate-Alkoxides of Titanium
Bijou, Diane,Cornier, Thibaut,Mishra, Shashank,Merzoud, Lynda,Chermette, Henry,Jeanneau, Erwann,Maudez, William,Benvenuti, Giacomo,Daniele, Stéphane
, p. 1976 - 1983 (2021)
A series of heteroleptic titanium derivatives of general formula [Ti(OiPr)2(R-acac)2] with acetylacetonate ligands modified in the internal (γ- or 3-) position by different substituents (R=OAc, NO2, Me, Et, Cl, Br) has been synthesized and completely characterized by liquid multinuclear NMR and FTIR. The influence of the nature of the group on the thermal stability of the different complexes was studied by thermogravimetric analysis (TGA) and gave the following decreasing stability ranking: H22°-acac radical, which triggers the decomposition.
β-DIKETONE INTERACTIONS Part 5. Solvent effects on the keto enol equilibrium
Emsley, John,Freeman, Neville J.
, p. 193 - 204 (1987)
The keto enol equilibrium of pentane-2,4-dione (PD) has been measured in 21 solvents at infinite dilution and a linear free energy relationship (LFER) tested againts four solvent polarity vectors: ε, ET, ?* and A + B.The best correlation coefficient is found for A +B.Similarly 3-methyl-pentane-2,4-dione (MePD) has been studied in 14 solvents and 3-ethylpentane-2,4-dione (EtPD) in six.The results suggest that the cyclic hydrogen bonding of the enol remains intact in all the solvents studied.
Chemoenzymatic Dynamic Kinetic Asymmetric Transformations of β-Hydroxyketones
Hilker, Simon,Posevins, Daniels,Unelius, C. Rikard,B?ckvall, Jan-E.
supporting information, p. 15623 - 15627 (2021/10/07)
Herein we report on the development and application of chemoenzymatic Dynamic Kinetic Asymmetric Transformation (DYKAT) of α-substituted β-hydroxyketones (β-HKs), using Candida antartica lipase B (CALB) as transesterification catalyst and a ruthenium complex as epimerization catalyst. An operationally simple protocol allows for an efficient preparation of highly enantiomerically enriched α-substituted β-oxoacetates. The products were obtained in yields up to 95 % with good diastereomeric ratios.
Size-Selective Hydroformylation by a Rhodium Catalyst Confined in a Supramolecular Cage
Nurttila, Sandra S.,Brenner, Wolfgang,Mosquera, Jesús,van Vliet, Kaj M.,Nitschke, Jonathan R.,Reek, Joost N. H.
supporting information, p. 609 - 620 (2019/01/04)
Size-selective hydroformylation of terminal alkenes was attained upon embedding a rhodium bisphosphine complex in a supramolecular metal–organic cage that was formed by subcomponent self-assembly. The catalyst was bound in the cage by a ligand-template approach, in which pyridyl–zinc(II) porphyrin interactions led to high association constants (>105 m?1) for the binding of the ligands and the corresponding rhodium complex. DFT calculations confirm that the second coordination sphere forces the encapsulated active species to adopt the ee coordination geometry (i.e., both phosphine ligands in equatorial positions), in line with in situ high-pressure IR studies of the host–guest complex. The window aperture of the cage decreases slightly upon binding the catalyst. As a result, the diffusion of larger substrates into the cage is slower compared to that of smaller substrates. Consequently, the encapsulated rhodium catalyst displays substrate selectivity, converting smaller substrates faster to the corresponding aldehydes. This selectivity bears a resemblance to an effect observed in nature, where enzymes are able to discriminate between substrates based on shape and size by embedding the active site deep inside the hydrophobic pocket of a bulky protein structure.
