Palladium‐Assisted “Aromatic Metamorphosis” of Dibenzothiophenes into Triphenylenes

Abstract Two new palladium‐catalyzed reactions of aromatic sulfur compounds enabled the conversion of dibenzothiophenes into triphenylenes in four steps. This transformation of one aromatic framework into another consists of 1) 4‐chlorobutylation of the dibenzothiophene to form the corresponding sulfonium salt, 2) palladium‐catalyzed arylative ring opening of the sulfonium salt with a sodium tetraarylborate, 3) an intramolecular S N 2 reaction to form a teraryl sulfonium salt, and 4) palladium‐catalyzed intramolecular CS/CH coupling through electrophilic palladation. Symmetrical as well as unsymmetrical triphenylenes of interest were synthesized in a tailor‐made fashion in satisfactory overall yields.