Efficient Entry to the Hasubarian Alkaloids: First Enantioselective Total Syntheses of (-)-Hasubanonine, (-)-Runanine, (-)-Delavayine, and (+)-Periglaucine B

摘要

We describe herein a simple and general logic strategy to synthesize the hasubanan alkaloids, a family of over 40 botanical natural products that share a common tetracyclic propellane skeleton (see structure 1, Figure 1). The versatility of our approach is evinced by the first enantioselective synthesis of (—)-hasubanonine (2), the foremost member of this family to be isolated, as well as by those of (-)-runanine (3), (-)-delavayine (4), and (+)-periglaucine B (5), in eight or nine steps from 5-(2-azidoethyl)-l,2,3-trimethoxy-benzene (6).