Isocoumarin Ring Rearrangement Approach to π-Extended Dibenzothiophenes

Abstract Sulfur-functionalized isocoumarins have been successfully converted into 1,2,3,4-tetrasubstituted naphthalenes through the addition of ketene silyl acetals and the subsequent skeletal rearrangement triggered by fluoride. The densely and consecutively substituted structures of the resulting naphthalene products have enabled further ring closure between adjacent substituents on the aromatic scaffolds to give several π-extended dibenzothiophenes.