Stereocontrolled Synthesis of the Tetracyclic Core Framework of (-)-Lemonomycin

Peter Siengalewicz, Lothar Brecker, Johann Mulzer*

Synlett (2008), (16), 2443-2446.

In a convergent approach, an advanced intermediate (2) in a projected total synthesis of the alkaloid (-)-lemonomycin (1) was prepared from readily available starting materials. The key transformations were a Pictet-Spengler cyclization, a Strecker-type amino alkylation, and an N-acyliminium cyclization.