Synthesis of 2-Alkylidenethietanes and the transformation to Thiophenes
Date of Issue2008
School of Physical and Mathematical Sciences
During the course of study on the nucleophilic substitution reaction at an sp2 carbon in the Narasaka group, a unique four-membered ring formation was realized by intramolecular nucleophilic vinylic substitution of a thiolate moiety. To generalize this 2-alkylidenethietane formation and to get more mechanistic information, synthesis of 2-alkylidenethietanes were examined by using this newly developed synthetic methodology. It was found that 2-alkylidenethietanes were oxidized to 2-alkylidenethietan- 1-oxides by treatment with m-CPBA, which has a unique structure with a strained four-membered ring, an exo double bond, and a sulfinyl group. Accordingly, the transformation of 2-alkylidenethietan-1-oxides were investigated. Incidentally, it was discovered that the treatment of 2-alkylidenethietan-1-oxides with p-toluenesulfonic acid afforded the unexpected thiophenes. The thiophene formation was extensively studied in this MSc’s thesis.