Total Synthesis of Laucysteinamide A, a Monomeric Congener of Somocystinamide A

Laucysteinamide A (4) is a marine natural product isolated from the cyanobacterium Caldora penicillata and contains structural motifs found in promising cancer drug leads. The first total synthesis of 4 and its analogues was achieved, which also enabled a concise formal synthesis of somocystinamide A (3), a dimeric congener of 4 that previously showed extremely potent antiproliferative activities. This work provides further insights on structure–activity relationships in this class of natural products.