An intensive bromination of 2,6-diaryl-4,4-diphenyl-4H-thiopyrans can lead through 3,5-dibromo derivatives to unexpected 2,8-diaryl-3-bromo- and 2,8-diaryl-3,5-dibromo-3a-phenyl-3aH-benzo[3,4]cyclopenta[1,2-b]thiophene as demonstrated on examples where the respective aryl groups are phenyl or 4-fluorophenyl. On the other hand, analogous spiro- [fluorene-9,4'-thiopyran]s do not exhibit the rearrangement evidently due to a rigid conformation of the fluorene moiety. The reaction mechanism for the rearrangement is proposed.
对2,6-二芳基-4,4-二苯基-4H-硫杂环戊烷进行强烈的溴化反应,可以通过3,5-二溴衍生物导致意外的2,8-二芳基-3-溴和2,8-二芳基-3,5-二溴-3a-苯基-3aH-苯并[3,4]环戊-[1,2-b]噻吩的形成,其中所述芳基基团分别为苯基或4-氟苯基。另一方面,类似的螺[芴-9,4'-硫杂环戊烷]不表现出明显的重排反应,可能由于芴基团的刚性构象。提出了重排反应的反应机理。