8-Oxabicyclo [3.2. 1] octan-3-one derivatives serve as excellent models that elucidate factors controlling the reactivities and selectivities in the Baeyer-Villiger oxidation. The regioselectivity of the oxidation with trifluoroperacetic acid is markedly affected by the electronic properties of substituents at position α or β to the carbonyl function. Remote effects of the γ-substituents are also of significance. This study has disclosed yet ...