Two different strategies for the synthesis of spongidines A and D are presented. Herein we describe a route based in an amino acid insertion followed by aromatization. Another alternative is the construction of a pyridine derivative followed by N-alkylation. Both methodologies have intermediate 5 as a key compound, which is eventually accessible from methyl isoanticopalate. (C) 2011 Elsevier Ltd. All rights reserved.
Synthesis of Spongidine A and D and Petrosaspongiolide L Methyl Ester Using Pyridine C–H Functionalization
strategy for the synthesis of the potent phospholipase A2 inhibitors spongidine A and D is presented. The tetracyclic core of the natural products was assembled via an intramolecular hydrogen atom transfer initiated Minisci reaction. A divergent late-stage functionalization of the tetracyclic ring system was also used to achieve a concise synthesis of petrosaspongiolide L methylester.