A solution of (4S,7R,8S,9S,16S,Z)-4,8-Bis((tert-butyldimethylsilyl)oxy)-5,5,7,9-tetramethyl-16-((E)-1-(2-methylthiazol-4-yl)prop-1-en-2-yl)oxacyclohexadec-13-ene-2,6-dione (26.2 mg, 37.1 μmol) in THF (3.6 ml) in a plastic vial was treated with HF-pyridine complex (70% HF, 1.09 mL). The reaction mixture was stirred at 22° C. for 36 h, diluted with DCM and quenched by NaHCO3 (sat.). The aqueous layer was extracted with DCM (2×). The combined organic layers were dried (MgSO4) and concentrated under reduced pressure. Purification on SiO2 (hexanes: diethyl ether 2:1 to 1:1) afforded 15.2 mg (81%, Z:E=95:5) of epothilone C as a colorless solid together with 2.6 mg of mono-desilylated product.
