Urea Activation of Nitrimines: A Mild, Metal-Free Approach to Sterically Hindered Enamines

Nitrimines have been identified as impressive starting points for the syntheses of otherwise inaccessible, sterically encumbered enamines. The activation of nitrimines with urea catalysts for reaction with a variety of amines enables the formation of highly substituted enamines in high yield. The reactions benefit from mild, metal-free conditions, high functional group tolerance, and straightforward scale up.