potassium hydroxide in ethanol; water 24 h; Heating;

1: methyl malonic acid diethylester With sodium hydride in diethyl ether; mineral oil 2.5 h; Reflux; 2: triiodomethane in diethyl ether; mineral oil 36 h; Reflux; 3: With potassium hydroxide in ethanol; water 24 h; Reflux;

copper(l) iodide; N,N-dimethyl-formamide; potassium iodide T=140°C; 5 h;

potassium hydroxide in ethanol; water 24 h; Heating;

1: With sodium hydride in diethyl ether T=20°C; 2.8 h; Inert atmosphereReflux; 2: With triiodomethane in diethyl ether 21.5 h; Inert atmosphereReflux; Further stages;

1: (1R,7S,8S,9S)-7-acetoxy-9-ethynyl-9-methyl-11-oxo-10-oxa-tricyclo[6.3.2.01,7]tridec-3-ene-4-carboxylic acid methyl ester With bis-triphenylphosphine-palladium(II) chloride; tri-n-butyl-tin hydride in tetrahydrofuran 0.25 h; Inert atmosphereReflux; 2: (E)-3-Iodo-2-methylpropen-2-oic Acid With tris(dibenzylideneacetone)dipalladium (0); N-ethyl-N,N-diisopropylamine in 1-methyl-pyrrolidin-2-one Stille coupling; 22 h;