Toward the Total Synthesis of Scabrosins: Synthesis of a Desulfur-scabrosin Skeleton and Its Stereoisomers

The enantioselective synthesis of a desulfur-scabrosin skeleton was reported. The synthesis began from 3-(hydroxymethyl)­phenol, and key steps include asymmetric nucleophilic epoxidation, a Mitsunobu reaction using a sulfonamide as the nucleophile, the construction of a pyrrolidine ring by intramolecular nucleophilic substitution, and inversion of configuration through base-induced keto–enol isomerization. Additionally, two isomers of the carbon skeleton were also obtained via an alternative ring-closing strategy.