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;

1.1: 70 percent / Mg / methanol / 12 h / 20 °C 2.1: 9 percent / O3 / CH2Cl2 / -78 °C 3.1: 34 percent / scandium triflate / acetonitrile / -20 - 0 °C 4.1: 53 percent / n-BuLi / tetrahydrofuran / -20 - 0 °C 5.1: potassium hexamethyldisilazane / tetrahydrofuran / -78 °C 5.2: PhSeCl / -23 °C 5.3: 31 percent / H2O2 / acetic acid View Scheme

1.1: 9 percent / O3 / CH2Cl2 / -78 °C 2.1: 34 percent / scandium triflate / acetonitrile / -20 - 0 °C 3.1: 53 percent / n-BuLi / tetrahydrofuran / -20 - 0 °C 4.1: potassium hexamethyldisilazane / tetrahydrofuran / -78 °C 4.2: PhSeCl / -23 °C 4.3: 31 percent / H2O2 / acetic acid View Scheme

1.1: 34 percent / scandium triflate / acetonitrile / -20 - 0 °C 2.1: 53 percent / n-BuLi / tetrahydrofuran / -20 - 0 °C 3.1: potassium hexamethyldisilazane / tetrahydrofuran / -78 °C 3.2: PhSeCl / -23 °C 3.3: 31 percent / H2O2 / acetic acid View Scheme

1.1: 53 percent / n-BuLi / tetrahydrofuran / -20 - 0 °C 2.1: potassium hexamethyldisilazane / tetrahydrofuran / -78 °C 2.2: PhSeCl / -23 °C 2.3: 31 percent / H2O2 / acetic acid View Scheme

1.1: LiAlH(OCMe3)3 / tetrahydrofuran / -78 °C 2.1: O3 / CH2Cl2 / -78 °C 3.1: 34 percent / scandium triflate / acetonitrile / -20 - 0 °C 4.1: 53 percent / n-BuLi / tetrahydrofuran / -20 - 0 °C 5.1: potassium hexamethyldisilazane / tetrahydrofuran / -78 °C 5.2: PhSeCl / -23 °C 5.3: 31 percent / H2O2 / acetic acid View Scheme

1.1: O3 / CH2Cl2 / -78 °C 2.1: 34 percent / scandium triflate / acetonitrile / -20 - 0 °C 3.1: 53 percent / n-BuLi / tetrahydrofuran / -20 - 0 °C 4.1: potassium hexamethyldisilazane / tetrahydrofuran / -78 °C 4.2: PhSeCl / -23 °C 4.3: 31 percent / H2O2 / acetic acid View Scheme