Rapid, high-yield, solid-phase synthesis of the antitumor antibiotic sansalvamide A using a side-chain-tethered phenylalanine building block

[GRAPHICS] A 10-step solid phase synthesis of the cytotoxic depsipeptide sansalvamide A (1) has been accomplished in an overall yield of 67% with >95% purity employing polymer-bound phenylalanine building block 2, Both the N- and C-termini of 2 are extended followed by on resin head-to-tail macrocyclization of the linear peptide in a high yield, This should be a general stategy for the synthesis of diverse libraries of cyclic peptides and depsipeptides that contain exclusively phenylalanine and other hydrophobic side chains.