Asymmetric Synthesis of (-)-Pterosin N from a Chiral 1,3-Dioxolanone

The first asymmetric total synthesis of (–)‐pterosin N from the N,N‐diisopropyl‐10‐camphorsulfonamide‐derived chiral 1,3‐dioxolanone 11 has been accomplished in 9 steps with 8 % overall yield. The key steps in this synthesis were the highly stereoselective propargylation of 1,3‐dioxolanone 11 to construct the chiral tertiary alcohol moiety, construction of a diene‐ynone by Stille coupling, and an intramolecular Diels–Alder reaction followed by aromatization to finish the synthesis. The first asymmetric total synthesis of (–)‐pterosin N was achieved in 9 steps in 8 % overall yield. The synthesis started from the asymmetric propargylation of a 1,3‐dioxolanone as precursor to establish the stereochemistry at C‐2. After some synthetic steps, including Stille coupling, intramolecular Diels–Alder reaction and aromatization, (–)‐pterosin N was obtained in enantiomerically highly pure form.