Enantioselective Rhodium-Catalyzed Hydrogenation of Enamides in the Presence of Chiral Monodentate Phosphanes

✍ Scribed by Stephan Enthaler; Bernhard Hagemann; Kathrin Junge; Giulia Erre; Matthias Beller

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 147 KB
• Volume: 2006
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200600024

✦ Synopsis

Abstract

The rhodium‐catalyzed asymmetric hydrogenation of different acyclic and cyclic N‐acyl enamides to give N‐acyl‐protected optically active amines has been examined for the first time in detail in the presence of chiral monodentate 4,5‐dihydro‐3__H__‐dinaphthophosphepines 5a–i. The enantioselectivity is largely dependent on the nature of the substituent at the phosphorus atom and the enamide substrate. Applying optimized conditions up to 95 % ee and catalyst activity up to 2000 h^–1^ (TOF) have been achieved.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)