Isomerization and Hydrogenation of Allylbenzenes Catalyzed by [RhH2(Ph2N3) (PPh3)2]
Noriyuki KAMEDA* and Tetsuya YONEDA
Department of Chemistry, College of Science and Technology, Nihon University; Narashinodai, Funabashi-shi 274-8501 Japan
The homogeneous isomerization and hydrogenation of allylbenzenes (allylbenzene, eugenol, 2-allylphenol and esdragole) catalyzed by [RhH2(Ph2N3) (PPh3)2] (dihydridorhodium complex) in dimethyl sulfoxide (DMSO) under a hydrogen@atmosphere (1 atm) at 303 K was studied. The highest catalytic activity was observed with allylbenzene as a substrate. The reaction products of isomerization and hydrogenation of allylbenzene were trans- and cis-1-propenylbenzene and propylbenzene. The isomerization rate under hydrogen atmosphere was faster than that under nitrogen atmosphere, suggesting that more active species were formed through the reaction of dihydridorhodium complex and hydrogen. A trace amount of the hydrogenated product was detected by use of other solvents (N,N-dimethylformamide, tetrahydrofuran, acetone, benzene and toluene). The mechanisms of isomerization and hydrogenation were proposed on the basis of present results together with our previous reports.
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