Preparation of Oxysterols by C–H Oxidation of Dibromocholestane with Ru(Bpga) Catalyst
Yui Fujii,
Makoto Yoritate,
Kana Makino,
Kazunobu Igawa,
Daiki Takeda,
Daiki Doiuchi,
Katsuhiko Tomooka,
Tatsuya Uchida,
Go Hirai
Affiliations
Yui Fujii
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Fukuoka, Japan
Makoto Yoritate
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Fukuoka, Japan
Kana Makino
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Fukuoka, Japan
Kazunobu Igawa
Institute for Materials Chemistry and Engineering, Integrated Research Consortium on Chemical Sciences (IRCCS), Kyushu University, Kasuga 816-8580, Fukuoka, Japan
Daiki Takeda
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Fukuoka, Japan
Daiki Doiuchi
Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Fukuoka, Japan
Katsuhiko Tomooka
Institute for Materials Chemistry and Engineering, Integrated Research Consortium on Chemical Sciences (IRCCS), Kyushu University, Kasuga 816-8580, Fukuoka, Japan
Tatsuya Uchida
Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Fukuoka, Japan
Go Hirai
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Fukuoka, Japan
Seven mono- and dihydroxycholesterols were prepared by direct C–H oxidation of the cholestane skeleton with a recently developed Ru(Bpga) catalyst (Ru(Bpga) = [RuCl (bpga) (PPh3)] Cl; bpga = 2-(bis(pyridin-2-ylmethyl)amino)-N-(2,6-dimethylphenyl)acetamide)). Due to the high selectivity of the Ru(Bpga) complex for tertiary C–H, the reaction afforded a mixture of 25-, 20-, 17-, and 14-oxygenated cholesterols that could be easily separated by high-performance liquid chromatography. These results suggest that late-stage C–H oxidation could be a viable strategy for preparing candidate metabolites of biologically important molecules.
