A Biomimetic Route for the Construction of the 4+2 and 3+2 Core Skeletons of the Dimeric Pyrrole-Imidazole Alkaloids and the Asymmetric Synthesis of Ageliferins

摘要

The pyrrole-imidazole alkaloids have fascinated chemists for decades because of their unique structures. The high nitrogen and halogen contents and the densely functionalized skeletons make their laboratory synthesis challenging. We describe herein an oxidative method for accessing the core skeletons of two classes of pyrrole-imidazole dimers. This synthetic strategy was inspired by the putative biosynthesis pathways and its development was facilitated by computational studies. Using this method, we have successfully prepared ageliferin, bromoageliferin, and dibromoageliferin in their natural enantiomeric form.