Fig. 3. Computed Gibbs energy profile for the 8-membered (left, N-cyclization) or 6-membered (right, C-cyclization) ring formation from the iminium intermediate C. Donor–donor (Ar¹, Ar² EDGs) energies in black and donor–acceptor (Ar¹ EDG, Ar² EWG) in magenta, all in kcal mol⁻¹.