Aminoalkylation of Electron-Rich Aromatic Compounds Using Performed Iminium Salts Derived from Aldehydes other than Formaldehyde

Abstract

Preformed iminium salts derived from aldehydes other than formaldehyde are demonstrated to be excellent reagents for the aminoalkylation of indoles, phenols and N,N-dimethylaniline. This method provides a simple and straightforward route to a variety of aromatic Mannich bases which are difficult to obtain by other procedures. Surprisingly, the reaction between N-methylindole or 2-naphthol with a preformed N-silyl iminium salt led to the formation of a bisindolylmethane or a dihydrooxazine derivative, respectively.