HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Special Issue
Ryoji Noyori's Special Issues, Vol. 76, No. 2, 2008
Published online: 16th June, 2008
■ Synthesis of Optically Active 1-Alkoxysilacyclopentane Derivatives
Kenichi Miyakawa, Eri Hamanishi, Koji Arimitsu, and Yukinori Nagao*
*Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
Abstract
The 1-chloro-2,5-dimethyl-1-phenyl-1-silacyclopentane was reacted with various optically active alcohols to give 1-alkoxysilacyclopentane derivatives, and some crystalline materials of the 1-alkoxysilacyclopentane derivatives could be separated from these stereoisomers for analysis by X-ray diffraction. Dimethyl-2,3-bis[(2,5-dimethyl-1-phenyl-1-silacyclopentyl)oxy]succinate and 2R-2-[(2,5-dimethyl-1-2-phenyl-1-silacyclopentyl)oxy]-1,1,2-triphenylethanol were synthesized.
Published online: 5th June, 2008
■ Asymmetric Synthesis of the Antiepileptic Drug Levetiracetam
Tatsushi Imahori, Keisuke Omoto, Yumi Hirose, and Hiroki Takahata*
*Faculty of Pharmaceutical Sciences, Tohoku Pharmaceutical University, Sendai 981-8558, Japan
Abstract
Palladium-catalyzed asymmetric synthesis of levetiracetam of antiepileptic drug was expediently accomplished.
Published online: 12th June, 2008
■ Catalytic Asymmetric Synthesis of (-)-Ritodrine Hydrochloride via Silyl Enol Ether Amination Using Dirhodium(II) Tetrakis[tetrafluorophthaloyl-(S)-tert-leucinate]
Masahiko Tanaka, Seiichi Nakamura, Masahiro Anada, and Shunichi Hashimoto*
*Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
Abstract
A catalytic asymmetric synthesis of (-)-ritodrine hydrochloride was achieved, incorporating an enantioselective amination of (Z)-silyl enol ether derived from 4-benzyloxypropiophenone with [(2-nitrophenylsulfonyl)imino]phenyliodinane (NsN=IPh) and a chelation-controlled reduction of the ketone carbonyl group with Zn(BH4)2 as the key steps. The use of dirhodium(II) tetrakis[tetrafluorophthaloyl-(S)-tert-leucinate] as a catalyst produced the targeted α-amino ketone in 94% yield with 91% ee.