Synthetic applications of umpoled vilsmeier reagents — A new simple one-pot route to isatins from formanilides

✍ Scribed by Otto Meth-Cohn; Simon Goon

• Book ID: 104258742
• Publisher: Elsevier Science
• Year: 1996
• Tongue: French
• Weight: 134 KB
• Volume: 37
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(97)82969-3

✦ Synopsis

When N-substituted formanilides are treated briefly and sequentially with oxalyl chloride, Hiinig's base, and bromine, isatins are rapidly formed, many in good yields. The reaction involves deprotenation of the Vilsmeier reag~t, dimerisation of the carbene thus formed and eleetrophilic cyelisation of the dimer by bromonium ion action followed by aqueous hydrolysis.