Aryl Trialkylsilyl Ketenes: Acid-Catalyzed Synthesis from 1-Aryl-2-diazo-2-trialkylsilylethanones and Their Conversion into 3-Silyl-1-silyloxyallenes

✍ Scribed by Stefan M. Bucher; Ralf Brückmann; Gerhard Maas

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 330 KB
• Volume: 2008
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200800524

✦ Synopsis

Abstract

Aryl‐substituted α‐silyl α‐diazo ketones are readily transformed into aryl silyl ketenes in the presence of a catalytic amount of triflic acid. Thus, a convenient method to prepare these silyl ketenes becomes available, which combines two steps, silylation of an aryl diazomethyl ketone and acid‐induced Wolff rearrangement of the formed α‐silyl α‐diazo ketone, in a one‐pot procedure. It appears that the trialkylammonium salt, which is formed in the silylation step, can also catalyze the Wolff rearrangement, but distinctly more slowly than the proton acid. The silyl ketenes react smoothly with α‐silyl α‐diazo ketones to form 3‐silyl‐1‐silyloxyallenes in fairly good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)