Total Synthesis of Dehydromicrosclerodermin D

Dehydromicrosclerodermin D is a cyclic hexapeptide containing several unusual amino acids, isolated from the marine sponge Theonella cupola. The first total synthesis of this compound is described in a convergent approach, via a novel synthetic strategy that incorporates the key constituent α,β-unsaturated γ-amino acid residue in a masked form; the final step of the synthesis implicates a domino demasking-cyclization-dehydration sequence.