Synthesis and Reactivity of Weiss Diketone Derivative Bearing Four Phenylsulfanyl Groups

Abstract

AbstractA bicyclo[3.3.0]octane‐3,7‐dione, bearing four phenylsulfanyl (PhS) groups at the diagonal α‐positions of the carbonyls, was synthesized as a key intermediate useful for exploring the regioselective transformations of symmetrical Weiss diketone. Tetra‐PhS‐substituted bicyclo[3.3.0]octane‐3,7‐dione was prepared by deprotonation of the Weiss diketone, using LDA in the presence of PhSSO2Ph. The tetra‐PhS‐substituted derivative thus obtained served as a scaffold for further regioselective base‐promoted enolization. Furthermore, the tetra‐PhS‐substituted Weiss diketone underwent an unexpected base‐promoted rearrangement to form isomeric tetra‐PhS‐substituted bicyclo[3.3.0]octane‐3,7‐dione through migration of PhS groups, likely through an interrupted Favorskii rearrangement.