Cerium-Catalyzed, Aerobic Oxidative Synthesis of 1,2-Dioxane Derivatives from Styrene and Their Fragmentation into 1,4-Dicarbonyl Compounds

✍ Scribed by Michael Rössle; Thomas Werner; Wolfgang Frey; Jens Christoffers

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 186 KB
• Volume: 2005
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200500487

✦ Synopsis

Abstract

1,4‐Diketones were prepared by cerium‐catalyzed oxidative coupling of styrene with molecular oxygen and 1,3‐dicarbonyl compounds. This two‐step sequence was performed as a one‐pot procedure without isolation of the intermediate products. The first step is a metal‐catalyzed radical reaction yielding 3‐hydroxy‐1,2‐dioxane derivatives being the cyclotautomers of initially formed 4‐hydroperoxy ketones. In the second step of this sequence, these endoperoxides are converted with AcCl–pyridine by Kornblum–DeLaMare fragmentation into the 1,4‐dicarbonyl motif. Several intermediate 1,2‐dioxane derivatives could be isolated and structurally characterized by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)