A New Method for the Synthesis of Nonsymmetrically Substituted Bis(azulen-1-yl) Ketones

✍ Scribed by Rolf Sigrist; Hans-Jürgen Hansen

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: German
• Weight: 288 KB
• Volume: 93
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.201000032

✦ Synopsis

Abstract

The 1‐(3‐methylazulen‐1‐yl)alkan‐1‐ones, when oxidized with excess 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (=4,5‐dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile; DDQ) in aqueous acetone in the presence of 1‐(3‐demethylazulen‐1‐yl)alkan‐1‐ones, form the corresponding unsymmetrically substituted bis(3‐acylazulen‐1‐yl)methanones in good to excellent yields (Schemes 4, 5, 7, and 10). Intermediates are the corresponding disubstituted methane derivatives, which are formed by radical and radical‐cation recombination (Scheme 6). The 1‐(3‐methylazulen‐1‐yl)alkan‐1‐ones can as well be coupled oxidatively with azulene itself, benz[a]azulene, or 1,3‐dimethoxybenzene (Schemes 9–11).