- Regioselective Ortho‐C–H sulfenylation of free phenols catalyzed by Co(II)-immobilized on silica-coated magnetic nanoparticles
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Fe3O4?SiO2-UT?CoII is prepared by the silica-coated magnetic nanoparticles, urea-triazole, and CoCl2. This organic-inorganic hybride composite showed a good to excellent catalytic activity toward regioselective ortho-sulfenylation of free phenols and naphthols using pivalic anhydride as a directing group, also K2S2O8 and PPh3 were employed as oxidant and additive respectively. The newly synthesized catalyst was fully characterized by using different techniques such as FT-IR, TGA, DTG, TEM, SEM, EDS, ICP and VSM analyses. The competitive price, accessibility and lower toxicity of cobalt compared to expensive transition metals using for C–H bond activation and functionalization constitute precious advantages for this method. Moreover, this heterogeneous catalyst could be magnetically recovered and reused without significant loss of its catalytic activity after five cycles.
- Khaef, Sepideh,Rostami, Abed,Khakyzadeh, Vahid,Zolfigol, Mohammad Ali,Taherpour, Avat Arman,Yarie, Meysam
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- FeCl3-mediated direct chalcogenation of phenols
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Direct sulfenylation and selenylation of phenols using a stoichiometric amount of FeCl3 under an oxygen atmosphere has been developed. The chalcogenated phenols were shown to be suitable for preparing S- and Se-containing compounds using the reaction of the remaining hydroxy group.
- Komeyama, Kimihiro,Aihara, Kiyoto,Kashihara, Tetsuya,Takaki, Ken
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supporting information; experimental part
p. 1254 - 1256
(2011/11/30)
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