C1-Symmetric Versus C2-Symmetric Ligands in Enantioselective Copper–Bis(oxazoline)-Catalyzed Cyclopropanation Reactions

✍ Scribed by José M Fraile; José I. García; Anja Gissibl; José A. Mayoral; Elísabet Pires; Oliver Reiser; Marta Roldán; Isabel Villalba

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 496 KB
• Volume: 13
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200700681

✦ Synopsis

Abstract

A thorough experimental and theoretical study of the enantioselective cyclopropanation of alkenes catalyzed by chiral bis(oxazoline)– and azabis(oxazoline)–copper complexes, which comprise a new family of ligands that lack C~2~ symmetry, has been conducted. Surprisingly high enantioselectivities were observed with some of these ligands, which were rationalized on the basis of molecular modeling studies. The course of the asymmetric induction in connection with ligand symmetry and the implications for supported enantioselective catalysts are discussed.