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Environmentally Friendly One‐Pot Synthesis of α‐Alkylated Nitriles Using Hydrotalcite‐Supported Metal Species as Multifunctional Solid Catalysts
Author(s) -
Motokura Ken,
Fujita Noriaki,
Mori Kohsuke,
Mizugaki Tomoo,
Ebitani Kohki,
Jitsukawa Koichiro,
Kaneda Kiyotomi
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600317
Subject(s) - hydrotalcite , catalysis , chemistry , alkylation , layered double hydroxides , hydroxide , palladium , reducing agent , aqueous solution , metal , inorganic chemistry , heterogeneous catalysis , organic chemistry
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 Å is observed on the Pd nano /HT surface by transmission electron microscopy analysis. These hydrotalcite‐supported metal catalysts can effectively promote α‐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 α‐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.