Protecting-Group-Free Total Synthesis of Chatenaytrienin-2

An efficient seven-step, protecting-group-free first total synthesis of chatenaytrienin-2 based on ring-closing metathesis and C(sp)-C(sp(3)) Sonogashira coupling with a 36.5% overall yield has been described. The ready availability of starting materials and key Wittig olefination, ring-closing metathesis, Lindlar reduction, and C(sp)-C(sp(3)) coupling makes this strategy applicable for the synthesis of various unbranched polyene-natural products with 1,5,9,n-(Z)-configured double bonds.