1189364-85-9Relevant academic research and scientific papers
METHOD OF PREPARING POLY(ALKYLENE CARBONATE) VIA COPOLYMERIZATION OF CARBON DIOXIDE/EPOXIDE IN THE PRESENCE OF NOVEL COMPLEX
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Paragraph 258; 259; 260; 261, (2014/10/04)
Provided is a method of preparing poly(alkylene carbonate) using a molecular weight regulator in a process of preparing a copolymer of carbon dioxide/epoxide using a novel complex synthesized from salen-type ligand including a quaternary ammonium salt as a catalyst. According to the present invention, even though the molecular weight regulator is used, an activity of the catalyst may be stably maintained, whereby the low molecular weight of poly(alkylene carbonate) having a desirable level may be effectively provided. In addition, it is expected that since the novel complex as the catalyst of the present invention has a simple structure as compared to the existing copolymerization catalyst, due to the economical preparation cost thereof, the novel complex may be effectively applied to a large-scale commercial process.
Mechanism and scope of salen bifunctional catalysts in asymmetric aldehyde and α-ketoester alkylation
Fennie, Michael W.,DiMauro, Erin F.,O'Brien, Erin M.,Annamalai, Venkatachalam,Kozlowski, Marisa C.
, p. 6249 - 6265 (2007/10/03)
Metal complexes of C2-symmetric Lewis acid/Lewis base salen ligands provide bifunctional activation resulting in rapid rates in the enantioselective addition of diethylzinc to aldehydes (up to 92% ee). Further experiments probed the reactivity of the individual Lewis acid and Lewis base components of the catalyst and established that both moieties are essential for asymmetric catalysis. These catalysts are also effective in the asymmetric addition of diethylzinc to α-ketoesters. This finding is significant because α-ketoesters alone serve as their own ligands to accelerate racemic 1,2-carbonyl addition of Et2Zn and racemic carbonyl reduction. The latter proceeds via a metalloene pathway, and often accounts for the predominant product. Singular Lewis acid catalysts do not accelerate enantioselective 1,2-addition over these two competing paths. The bifunctional amino salen catalysts, however, rapidly provide enantioenriched 1,2-addition products in excellent yield, complete chemoselectivity, and good enantioselectivity (up to 88% ee). A library of the bifunctional amino salens was synthesized and evaluated in this reaction. The utility of the α-ketoester method has been demonstrated in the synthesis of an opiate antagonist.
Salen-derived catalysts containing secondary basic groups in the addition of diethylzinc to aldehydes
DiMauro, Erin F.,Kozlowski, Marisa C.
, p. 3053 - 3056 (2007/10/03)
matrix presented A set of modular bifunctional salen catalysts which contain Lewis acid and Lewis base activating groups is described. These groups can be altered independently to control nucleophilic and electrophilic activation of the reacting substrates. These salen-derived catalysts show enhanced reactivity in the addition of diethylzinc to aldehydes with respect to most other salen, amino alcohol, and diamine derived catalysts and reactivity comparable to that of Ti complexes of bis-sulfonamides and diols.
Supramolecular assemblies from ditopic ligands and transition metal salts
Miller, Hamish A.,Laing, Norman,Parsons, Simon,Parkin, Andrew,Tasker, Peter A.,White, David J.
, p. 3773 - 3782 (2007/10/03)
Tetradentate salicylaldimine ligands of the H2salen-type bearing ort/io-A'-morpholinomethyl substituents function as ditopic ligands, bonding to Ni" or Cu" with the [N2O2]2" donor set of the salen unit and a sulfate or two nitrate anions with the protonat
