Double Stereochemical Labeling in Stilbene Photochemistry: Tracing Phenyl Rotation Reveals Stereochemically Distinct Reaction Pathways for Formation of the E Photoproducts

摘要

Saltiel's observation of emission from the excited state of 1 upon excitation of 2 provides direct evidence for the existence of a common intermediate ([1]~p) along the stilbene S_1 surface. The stereochemical studes herein provide a second piece of evidence supporting such an intermediate and a new photo- chemical isomerization reaction: syn/anti isomerization.