A Novel Rearrangement in the Sterically Congested (2,4,6- Cycloheptatrienyl)(phenylsulfinyl)methyl Group.

An oxidation product of 3-bromo-1-formyl-4-[(2,4,6-cycloheptatrienyl)(phenylthio)methyl]azulene with m-chloroperbenzoic acid was transformed into 3-bromo-1-formyl-4-(E)-styrylazulene upon standing at 0 °C in a solid state. A similar rearrangement was also observed in the oxidation of 3-chloro-1-methyl-[(2,4,6-cycloheptatrienyl)(phenylthio)methyl]azulene.