10.1021/acs.jpclett.6b02632.s001 Nobuo Matsuki Nobuo Matsuki Yoshihisa Inoue Yoshihisa Inoue Tadashi Mori Tadashi Mori Orbital Control of Photochemical Rearrangement of 4‑Aryl-1,1-dicyano-1-butenes through the Hyperconjugative Substitution on the Linker Chain American Chemical Society 2016 hyperconjugation benzylic position photochemistry photoreactivity strength Linker Chain Hyperconjugative interaction conformer distribution 4- role Photochemical Rearrangement Hyperconjugative Substitution allylic rearrangement product outcome Aryl substituent parent substrate analysis Orbital Control aryl contribution bond 2016-11-14 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Orbital_Control_of_Photochemical_Rearrangement_of_4_Aryl-1_1-dicyano-1-butenes_through_the_Hyperconjugative_Substitution_on_the_Linker_Chain/4246709 Hyperconjugative interaction was demonstrated to play a vital role in the photochemistry of 4-aryl-1,1-dicyano-1-butenes. Thus a simple substituent on the benzylic position effectively induced a new photoreactivity to afford an allylic rearrangement product that is not obtained for the parent substrate. The natural bond orbital analysis was employed to reveal the enhanced relative contributions of hyperconjugation in the excited state, which dramatically alter the photochemical outcomes not only by reducing the strength of the allylic/benzylic bond but more crucially by affecting the conformer distribution.