Photocycloaddition of acetylacetonatoboron derivatives with simple olefins (original) (raw)

Acetylacetonatoboron di uoride (AABF 2 / and oxalate (AABO) undergo cycloaddition from their singlet excited state with cyclic and terminal ole ns to give stereospeci c but nonregiospeci c products; the latter oxalate reacted slightly faster than the former di uoride. A conjugated diene, 1,3-cyclooctadiene,and methyl substituted benzenes also reacted similarly but with slower rates owing to electron transfer at the encounter stage. The resulting radical ion pairs may undergo radical ion type reactions and/ or reverse electron transfer, which leads to the partial waste of the photoenergy. For the same reasons, the reaction occurs more ef ciently in non-polar solvents, such as ether, dioxane and methylene chloride than in acetonitrile.