Highly Selective Linear Dimerization of Styrenes by Ceria‐Supported Ruthenium Catalysts

Abstract

Ceria‐supported ruthenium (Ru/CeO2) was found to be an effective catalyst for linear‐selective dimerization of styrenes. The dimerization of styrene in the presence of Ru/CeO2 together with ethanol and formalin in mesitylene at 150 °C gave (E)‐1,4‐diaryl‐1‐butene in 63 % yield with high linear selectivity (95 %). The presence of ethanol and/or formaldehyde is indispensable. Whereas a zirconia‐supported ruthenium showed moderate activity, catalysts supported on other metal oxides were not effective at all. The hot filtration tests indicated that the Ru/CeO2 catalyst acts heterogeneously. The leaching of ruthenium species into the solution was negligible according to analysis by using inductively coupled plasma atomic emission spectroscopy. The regioselectivity can be switched through the choice of a suitable solvent: the reactions in N,N‐dimethylacetamide or N‐methyl‐2‐pyrrolidone gave the corresponding branched dimers in good yields with complete regioselectivity.

Bimetallic nanosized solids with acid and redox properties for catalytic activation of C–C and C–H bonds

“…Ru supported on CeO 2 , and using formaldehyde or ethanol as promoters to give a 63% yield of 1,4-diaryl-1-butenes. 14 Fe 2 (NTf 2 ) 5 O@AgNPs catalyzes the regioselective head-to-tail dimerization of styrenes 1a–c to 2a–c in yields up to 98%. The hot filtration test for styrene 1a showed that the catalytic activity completely stops when the solid catalyst is filtered off, which confirms the heterogeneous nature of the catalysis.…”

グリーン有機分子変換プロセスを指向したセリア担持ルテニウム触媒の開発

“…We next tried to expand the scope of the present catalytic system to the dimerization of styrenes 42) . The reaction of styrene (14), however, did not proceed at all with Ru/CeO2, even in the presence of sodium formate.…”

“…The success of our first attempt prompted us to examine the effectiveness of Ru/CeO2 as a solid catalyst alternative to low-valent ruthenium complex catalysts, and we have revealed that Ru/CeO2 could realize various organic transformations, including reactions that proceed C _ H bond activation 40) 46) . Some of these reactions are effectively promoted by the Ru/CeO2 catalyst together with a small amount of additives 41), 42) , and some other reactions require the reductive treatment of Ru/CeO2 in the presence of specific phosphines 43),44), 46) . The present account describes our recent results in the development of a Ru/CeO2-based catalytic system for use in environmentally-benign organic transformations.…”

Multiple linear regression and artificial neural networks for highly selective cationic β‐diimine‐methallyl nickel (II) catalyst for styrene dimerization reaction to 1,3‐diphenyl‐1‐butene

“…While nickel catalysts are known to produce a high yield of styrene dimers, with selectivity to para-dimer. [13][14][15] We have developed a one-pot method for preparing cationic methallyl-β-diimine-nickel (II) complexes [(η 3methallyl)Ni(β-diimine)][PF 6 ] (I) starting from (β-diimine)NiBr 2 , zinc, and [(η 1 -C 4 H 7 )OP (NMe 2 ) 3 ][PF 6 ] by the following general equation (Equation (1)) 16 :…”

“…For example, Palladium catalysts are known to produce a high yield of styrene dimers, with selectivity to ortho‐dimer and meta‐dimer. While nickel catalysts are known to produce a high yield of styrene dimers, with selectivity to para‐dimer 13–15 …”