19672-37-8Relevant articles and documents
Catalytic tandem C-C bond formation/cleavage of cyclopropene for allylzincation of aldehydes or aldimine using organozinc reagents
Nakano, Takeo,Endo, Kohei,Ukaji, Yutaka
supporting information, p. 1418 - 1421 (2014/04/03)
The tandem allylation of aldehydes or an aldimine with allylzinc intermediates derived from organozinc reagents and cyclopropenes is described. The present three-component reaction involves carbozincation of cyclopropene and sequential cleavage of a cyclopropylzinc intermediate in situ without a transition-metal catalyst. The allylzinc intermediates generated in situ, which is an α,β-unsaturated acylanion equivalent, gave the corresponding homoallylic alcohols or amine in good yields.
H5CoW12O40 supported on nano silica from rice husk ash: A green bifunctional catalyst for the reaction of alcohols with cyclic and acyclic 1,3-dicarbonyl compounds
Rafiee, Ezzat,Khodayari, Maryam,Kahrizi, Masoud,Tayebee, Reza
experimental part, p. 121 - 128 (2012/06/01)
Rice husk ash (RHA) is an abundant agricultural by-product. The present research work deals with the production of nano silica powders, with high surface area and in amorphous form, from RHA using optimized technique. 12-Tungestocobaltic acid, H5CoW12O40 (CoW), was supported on silica from RHA to produce silica supported CoW (CoW/NSiO 2) as a nano catalyst. The characterization data derived from FT-IR reveal that the Keggin structure of CoW remains intact in CoW/NSiO2. TEM image showed that the catalyst had spherical shape with an average particle size of 10 nm. The acidity of the catalyst was measured by potentiometric titration with n-butylamine. To our surprise, this very strong solid acid catalyst showed an excellent distribution of acid sites, suggesting that the catalyst possesses a higher number of surface active sites compared to CoW supported on commercial silica (CoW/SiO2), CoW and K 5CoW12O40. A high catalytic activity was found over CoW/NSiO2. Finally, CoW/NSiO2 has been used as a highly effective catalyst for benzylation of linear 1,3-dicarbonyl compounds with benzylic alcohols and synthesis of β-keto enol ethers from cyclic 1,3-dicarbonyl compounds. The present methodology offers a practical, simple, mild, environmentally friendly, and timesaving method under solvent-free conditions.
Fe(ClO4)3·×H2O-Catalyzed direct C-C bond forming reactions between secondary benzylic alcohols with different types of nucleophiles
Thirupathi, Ponnaboina,Kim, Sung Soo
experimental part, p. 2995 - 3003 (2010/06/14)
Fe(ClO4)3·×H2O as a highly effective catalyst for benzylation of 1,3-dikones, β-ketoesters, 1,3-diesters, electron-rich arenes and heteroarenes and 4-hydroxycoumarin with various benzylic alcohols is described. The usefulness of this procedure is shown by a synthesis of bis-symmetrical triarylmethanes and one step synthesis of an anti-coagulant compound 4-hydroxy-3-(1,2,3,4-tetrahydronaphthalen-1-yl)-2H-chromen-2-one (Coumatetralyl (B)). The advantages of this protocol are broad scope, mild conditions, use of inexpensive catalyst and simplicity of operation since water is the only side product.
