Construction of a C(30−38) Dioxabicyclo[3.2.1]octane Subtarget for (+)-Sorangicin A, Exploiting a Regio- and Stereocontrolled Acid-Catalyzed Epoxide Ring Opening

In this paper, we report assembly of the novel dioxabicyclo[3.2.1]octane subtarget (−)-2, comprising the signature structural element of the potent antibiotic (+)-sorangicin A (1). The synthesis was achieved in 15 steps (1.5% overall yield) via a series of acid-catalyzed epoxide ring openings. The first, facilitated by the complex of alkyne (+)-3 with Co₂(CO)₈, proceeded in a highly regio- and stereoselective fashion.