Cerium-Catalyzed α-Hydroxylation Reactions of α-Cyclopropyl β-Dicarbonyl Compounds with Molecular Oxygen

✍ Scribed by Jens Christoffers; Thomas Kauf; Thomas Werner; Michael Rössle

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 158 KB
• Volume: 2006
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200600061

✦ Synopsis

Abstract

Three α‐cyclopropyl β‐dicarbonyl compounds have been used as probes for α‐radicals as electrophilic reaction intermediates in a cerium‐catalyzed α‐hydroxylation reaction with molecular oxygen. Since the cyclopropyl group did not ring‐open to products with a butenyl moiety, but was retained in the products, a localized unpaired electron at the α position can be excluded during the course of the reaction. The α‐cyclopropyl‐substituted substrates were prepared by aldol or Claisen reactions. Other substrates with α‐methyl, α‐isopropyl, and α‐tert‐butyl substituents were prepared and converted under the α‐hydroxylation conditions in order to estimate steric influences on the yield of the reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)