Aluminum chloride-catalyzed rearrangement of aryl sulfides leads to thermodynamically controlled equilibrium mixtures at room temperature. On treatment of o-, m- or p-tolyl phenyl sulfide without solvent, the isomer distribution converges to an equilibrium point, 17% ortho, 47% meta and 36% para isomer by intramolecular isomerization. Intermolecular disproportionation by methyl-group exchange to produce diphenyl sulfide and ditolyl sulfide accompanied isomerization. In addition, a new type of aromatic rearrangement, intermolecular disproportionation by exchange of the arylthio group, was found to occur simultaneously giving benzene, toluene and thianthrene derivatives. The rate of this reaction is slower than that of the methyl rearrangement. A similar treatment of α-naphthyl phenyl sulfide gave the β-isomer from intramolecular isomerization and diphenyl sulfide, naphthalene, thianthrene and benzene from intermolecular disproportionation. The mechanisms of the rearrangement of aryl sulfides are discussed.
Die A1‐chlorid‐katalysierte Umlagerung von o‐, m‐ und p‐Tolyl‐phenylsulfid bei Raumtemperatur führt jeweils zu einem thermodynamisch kontrollierten Gleichgewichts‐Gemisch aller 3 Isomeren (I).
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