Activation of 2‐Cyclohexenone by BF ₃ Coordination: Mechanistic Insights from Theory and Experiment

Lewis acids have recently been recognized as catalysts enabling enantioselective photochemical transformations. Mechanistic studies on these systems are however rare, either due to their absorption at wavelengths shorter than 260 nm, or the limitations of theoretical dynamic for larger complexes. In this work, we overcome challenges and employ sub-30-fs transient in UV, combination with a highly accurate treatment XMS-CASPT2 level. We investigate 2-cyclohexenone its complex boron trifluoride analyze observed dynamics based trajectory calculations including non-adiabatic coupling intersystem crossing. This approach explains all ultrafast decay pathways complex. show that acid remains attached substrate triplet state, which turn why chiral boron-based induce high enantioselectivity photocycloaddition reactions.