Reusable Catalysts for the Asymmetric Diels–Alder Reaction

✍ Scribed by Guillaume Chollet; Marie-George Guillerez; Emmanuelle Schulz

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 208 KB
• Volume: 13
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200601081

✦ Synopsis

Abstract

A new method for recycling chiral bis(oxazoline)–copper complexes is described based on the formation of charge‐transfer complexes, their subsequent precipitation, and reuse after addition of new substrates. The conditions to perform this procedure were optimized in the presence of three bis(oxazoline)‐based ligands. When associated with copper salts, these ligands efficiently catalyzed the Diels–Alder reaction between cyclopentadiene and α,β‐unsaturated acyloxazolidinones. These catalysts were successfully recycled up to ten times while maintaining their high activities and enantioselectivities.