Alkylation and silylation of directed enolates from diethylketene and organometallic reagents

✍ Scribed by Thomas T. Tidwell

• Book ID: 104238000
• Publisher: Elsevier Science
• Year: 1979
• Tongue: French
• Weight: 180 KB
• Volume: 20
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)86664-8

✦ Synopsis

Diethylketene and organometallic reagents form enolates capturable by methyl iodide or trimethylsilyl chloride with greater than 95% positional selectivity. Despite their multiple functionality and high reactivity ketenes have found only limited utility as laboratory scale synthetic reagents.' Instead the use of "ketene equivalents"2a and "masked ketenes" 2b has been emphasized. A recent review on preparative applications of ketenes emphasizes cycloadditions and states "ketene acylation reactions are generally not useful synthetically. ,,ld Only occasional examples are reported of advantageous use of ketenes in synthesis, 3 although there has been intense recent interest in the reaction mechanisms of ketenes and related species4 and in their role as reaction intermediates.