A pathway is proposed for the biosynthesis of the unique homodimeric terpene, halichonadin
H. The proposed biosynthetic pathway involves two key Passerini reactions of eudesmane-type
terpene isocyanides. The Passerini reaction of a model terpene isocyanide and formaldehyde
afforded an α-hydroxy acetamide, which was further subjected to oxidation and a second
Passerini reaction. This reaction sequence furnished an α-hydroxy malonamide connected
with two identical terpene units which is the identical structural motif found in
halichonadin H.
Key words
marine natural products - terpenes - isocyanides - biosynthesis - Passerini reaction