A recyclable dendritic osmium catalyst for homogeneous dihydroxylation of olefins |
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Authors: | Ken-ichi Fujita Manabu Yamazaki Teruhisa Tsuchimoto |
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Institution: | a National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan b Department of Applied Chemistry, School of Science and Technology, Meiji University, Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan |
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Abstract: | A series of osmate (OsO42−) core dendrimers was prepared by an ion-exchange technique through the mixing of K2OsO4 and a bis(quaternary ammonium bromide) core dendrimer, which consisted of poly(benzyl ether) dendron. By employing an osmate core dendrimer as a homogeneous catalyst, dihydroxylation reactions of olefins proceeded rapidly, and the dendritic osmium catalyst was recovered by reprecipitation and then reused. Furthermore, a dendritic effect on the recyclability of a catalyst was observed. In the case of asymmetric dihydroxylation reactions, the corresponding diol was obtained in a high chemical yield with a fair enantiomeric excess (ee). In this case, not only the dendritic osmium catalyst but also the chiral ligand could be recovered by reprecipitation and reused efficiently up to five times. |
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Keywords: | MFCKBSBOLAGSLO-UHFFFAOYSA-N |
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