Synthesis of spongidines A and D: marine metabolites phospholipase A2 inhibitors

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.