Synthesis of the C6–C21 fragment of epothilone analogues

(2S,4E,6Z,9S,10E)-9-[tert-Butyl(diphenyl)silyloxymethyl]-2,6,10-trimethyl-11-(2-methylthiazol-4-yl)undeca-4,6,10-trien-1-ol, a key precursor for epothilone analogues, was prepared by multi-step synthesis using the Julia–Kocienski olefination at the key step.