41246-22-4Relevant academic research and scientific papers
Template catalysis by manganese pincer complexes: Oxa- and aza-Michael additions to unsaturated nitriles
Tang, Shan,Milstein, David
, p. 8990 - 8994 (2019/10/22)
Activation of CN bonds by metal-ligand cooperation provides a new route for the functionalization of nitriles. Herein, we report the electrophilic activation of unsaturated nitriles by dearomatized manganese pincer complexes for the oxa- and aza-Michael addition reactions under very mild and neutral conditions. Derivatives of acrylonitrile and allyl cyanide furnished the corresponding β-addition products by reacting with alcohols and amines. Mechanistically, the catalysis is mostly ligand based. Reaction of the dearomatized PNN-Mn complex with 2-pentenenitrile or 3-pentenenitrile furnished an enamido-Mn complex. The equilibrium between an enamido complex and a ketimido complex, and reversible C-C bond formation with the ligand are proposed to play central roles in the catalysis.
Addition of alcohols to acrylic compounds catalyzed by Mg-Al LDH
Teodorescu,Deaconu,Bartha,Z?voianu,Pavel
, p. 117 - 122 (2014/03/21)
This study reports the preparation of hydrotalcite with Mg/Al molar ratio 3 by co-precipitation under low suprasaturation conditions of Mg and Al nitrated solutions with Na2CO3 and NaOH at pH 10. The solid was thermally decomposed at 460°C in air atmosphere in order to obtain mixed oxides which, by means of memory effect, can reconstruct the hydrotalcite structure by hydration with bidistilled water. The hydrotalcite and reconstructed samples by memory effect were characterized by elemental analysis, powder XRD, DRIFT and TG-DTG. Determination of the catalysts surface base sites was made using a method based on the irreversible adsorption of organic acids with different pKa values and N2 adsorption-desorption isotherms. The catalytic activity of these solids was evaluated in 1,4-addition of saturated linear alcohols to different acrylic compounds. All these reactions arose with high selectivity in the desired product. No by-products were detected by means of GC-MS chromatography and 1H NMR.
Ligand-free nickel-catalyzed conversion of aldoximes into nitriles
Li, Yen-Ting,Liao, Bei-Sih,Chen, Hsin-Pei,Liu, Shiuh-Tzung
experimental part, p. 2639 - 2643 (2011/10/04)
Catalytic dehydration of aldoximes can be performed efficiently with NiCl2 in acetonitrile under neutral and mild conditions. Under these conditions, various functionalized aldoximes produce the corresponding nitriles in good to excellent yields. Georg Thieme Verlag Stuttgart. New York.
Novel amine-catalysed hydroalkoxylation reactions of activated alkenes and alkynes
Murtagh, Julie E.,McCooey, Seamus H.,Connon, Stephen J.
, p. 227 - 229 (2007/10/03)
Substoichiometric loadings of DBU catalyse the efficient 1,4-addition of alcohols and non-nucleophilic amines such as pyrrole to activated alkenes; the application of this methodology in a one-pot synthesis of a natural product, and as a novel strategy for the synthesis of mono-protected 1,3-carbonyl compounds is reported.
Effect of pressure on sterically congested cyanoalkylation reactions of alcohols
Jenner
, p. 4311 - 4317 (2007/10/03)
The pressure effect on the phosphine-catalyzed nucleophilic addition of alcohols to unsaturated nitriles is examined. As a general result, pressure promotes these reactions. Their sensitivity to pressure increases with increasing steric congestion of either the alcohol or the nitrile. Activation volumes are found to be very negative pointing not only to a late transition state, but essentially to a considerable electrostriction contribution depending on steric hindrance to ionization. This means that pressures favors formation of the carbanion and attack of the nitrile. The results highlight the synthetic utility of high pressure to remove steric inhibition.
