Isolation of lomaiviticins C-E, transformation of lomaiviticin C to lomaiviticin A, complete structure elucidation of lomaiviticin A, and structure-activity analyses.

We describe the isolation of (-)-lomaiviticins C-E (6-8), elucidation of the complete absolute and relative stereochemistry of (-)-lomaiviticin A (1), the synthetic conversion of (-)-lomaiviticin C (6) to (-)-lomaiviticin A (1), and the first evidence that the dimeric diazofluorene of (-)-lomaiviticin A (1) plays a defining and critical role in antiproliferative activity.