Industrially Viable Syntheses of Highly Enantiomerically Enriched 1-Aryl Alcohols via Asymmetric Hydrogenation

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• 作者：David Chaplin ; Paul Harrison ; Julian P. Henschke ; Ian C. Lennon ; Graham Meek ; Paul Moran ; Christopher J. Pilkington ; James A. Ramsden ; Simon Watkins ; and Antonio Zanotti-Gerosa
• 刊名：Organic Process Research & Development
• 出版年：2003
• 出版时间：January 2003
• 年：2003
• 卷：7
• 期：1
• 页码：89 - 94
• 全文大小：84K
• 年卷期：v.7,no.1(January 2003)
• ISSN：1520-586X

文摘

The practicalities of the asymmetric hydrogenation of acetophenone derivatives are addressed. The catalysts used, derived fromthe precatalysts [(xylylPhanePhos)RuCl₂(DPEN)] (S)-(R,R)-1and (R)-(S,S)-1, were shown to possess very high reactivity. 4'-Fluoroacetophenone was hydrogenated at a molar substrate-to-catalyst ratio (S/C) of 100,000 with complete conversioneffected in as little as 80 min (average turnover ~1200 min^-1,peak turnover ~2500 min^-1). The catalysts are tolerant of arange of commercial grade substrates, in most cases a S/C of5000-10000 was achieved without the need to purify the ketone.Using precatalyst 1 enantioselectivities of 95 f"> 99% ee wereachieved. The high selectivity and catalyst activity, plus thesimplicity of the process, offers significant advantages over otherenantioselective ketone reductions.