Environmentally friendly one-pot synthesis of alpha-alkylated nitriles using hydrotalcite-supported metal species as multifunctional solid catalysts.
A ruthenium-grafted hydrotalcite (Ru/HT) and hydrotalcite-supported palladium nanoparticles (Pd(nano)/HT) are easily prepared by treating basic layered double hydroxide, hydrotalcite (HT, Mg(6)Al(2)(OH)(16)CO(3)) with aqueous RuCl(3)n H(2)O and K(2)[PdCl(4)] solutions, respectively, using surface impregnation methods. Analysis by means of X-ray diffraction, and energy-dispersive X-ray, electron paramagnetic resonance, and X-ray absorption fine structure spectroscopies proves that a monomeric Ru(IV) species is grafted onto the surface of the HT. Meanwhile, after reduction of a surface-isolated Pd(II) species, highly dispersed Pd nanoclusters with a mean diameter of about 70 A is observed on the Pd(nano)/HT surface by transmission electron microscopy analysis. These hydrotalcite-supported metal catalysts can effectively promote alpha-alkylation reactions of various nitriles with primary alcohols or carbonyl compounds through tandem reactions consisting of metal-catalyzed oxidation and reduction, and an aldol reaction promoted by the base sites of the HT. In these catalytic alpha-alkylations, homogeneous bases are unnecessary and the only by-product is water. Additionally, these catalyst systems are applicable to one-pot syntheses of glutaronitrile derivatives.
Motokura
Ken
K
Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
Fujita
Noriaki
N
Mori
Kohsuke
K
Mizugaki
Tomoo
T
Ebitani
Kohki
K
Jitsukawa
Koichiro
K
Kaneda
Kiyotomi
K
D000478:Alkylation; D000536:Aluminum Hydroxide / Q000737:chemistry*; D002384:Catalysis; D008276:Magnesium Hydroxide / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D053758:Nanoparticles; D009570:Nitriles / Q000138:chemical synthesis*; D010165:Palladium / Q000737:chemistry; D017975:Ruthenium Compounds / Q000737:chemistry; D013057:Spectrum Analysis; D014961:X-Ray Diffraction
D008670:Metals; D009570:Nitriles; D017975:Ruthenium Compounds; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D010165:Palladium; D008276:Magnesium Hydroxide; C038365:ruthenium chloride