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.

Spongidines A and D have been synthesized. Two routes have been optimized and the key compound is chloroderivative 13.