Total Synthesis of the Thiazolyl Peptide GE2270 A

When one door closes, another opens: In the synthesis of the thiazolyl peptide GE2270 A (1), the bonds labeled I and II at the pyridine core were established by two consecutive cross-coupling reactions. Amide bond formation (IV) and subsequent intramolecular Stille reaction (III) were more effective than the originally conceived connection strategy (III before IV). GE2270 A (1) was prepared with an overall yield of 4.8 % in 20 steps along the longest linear sequence.