Direct Substitution of 2-Aminotropones with Potassium Allyltrifluoroborates through Transition-Metal-Free C−N Bond Cleavage

Abstract

The poor nucleofugality of the amino group renders the C−N bond functionalization of primary aromatic amines highly challenging. Herein, we report a direct substitution reaction of 2-aminotropones, bearing a unique non-benzenoid seven-membered aromatic ring that exists in some natural products and bioactive molecules, with potassium allyltrifluoroborates through C−N bond cleavage under transition-metal-free conditions. The amino group of 2-aminotropones were directly substituted with potassium allyltrifluoroborates in the presence of sodium bicarbonate, delivering structurally diverse 2-allyltropones in moderate to good yields. The reaction is free of directing groups, activating groups and transition metals, providing a convenient method to access substituted tropones.