Abstract:
The first total synthesis of the ascidian blood pigment tunichrome Sp-1 is reported, with the modified pentapeptide prepared in a convergent manner using a combination of solid-phase peptide synthesis, Hunsdiecker decarboxylative iodination and Buchwald amidation reaction chemistry. The natural product was shown to exist as a mixture of trans- and cis-prolyl conformers, with the former dominating in a 5:1 ratio.