HERON reactions of anomeric amides: understanding the driving force

HERON reactions of anomeric amides: understanding the driving force
Journal of Physical Organic Chemistry, 2015, 28 (3), 215-222
S. A. Glover and A. A. Rosser

The HERON (Heteroatom Rearrangement On Nitrogen) reaction has been observed only in select anomeric amides; amides possessing low amide resonance, bearing two electronegative heteroatoms at the amide nitrogen.  In this paper, using density functional theory, we demonstrate how the activation barrier for the HERON reaction can be separated into two components, the energy required to overcome amide resonance and the energy required for rearrangement, and that without the reduction of the amide resonance component, the activation barrier for the HERON reaction remains prohibitively large.