Synthesis of the C9–C29 fragments of ajudazols A and B

The syntheses of both C9–C29 fragments 3 and 4 of the myxobacteria metabolites ajudazols A (1) and B (2) are described. The key steps were a cyclodehydration to form the oxazole, Sonogashira coupling to form the C18–C19 bond and a P-2 Ni mediated partial alkyne hydrogenation to install the C17–C18 Z-alkene. The C15 alkene in the ajudazol A fragment 3 was introduced in the final steps by elimination of the corresponding primary alcohol.