1.1: toluene-4-sulfonic acid / dichloromethane / 1 h / 20 °C / Inert atmosphere 2.1: isopropylmagnesium chloride / tetrahydrofuran / 0.58 h / -20 - -5 °C / Inert atmosphere 3.1: diethyl ether; hexane / 2 h / -78 - 20 °C / Inert atmosphere 4.1: potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / -78 °C / Inert atmosphere 4.2: 0.67 h / Inert atmosphere 5.1: toluene-4-sulfonic acid / methanol / 0.5 h / 20 °C / Inert atmosphere 6.1: tetrakis(triphenylphosphine) palladium(0); lithium chloride / diethyl ether / 0 °C / Inert atmosphere 6.2: 1 h / Inert atmosphere 7.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 0 °C / Inert atmosphere 8.1: sodium carbonate / N,N-dimethyl-formamide / 30 h / 80 °C / Inert atmosphere 9.1: lithium perchlorate; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 0.33 h / 20 °C / Molecular sieve; Inert atmosphere 10.1: osmium(VIII) oxide; water / tetrahydrofuran / 0.25 h / 0 °C / Inert atmosphere 10.2: 5 h / 0 °C / Inert atmosphere 11.1: sodium tetrahydroborate / ethanol / 1 h / 0 - 20 °C / Inert atmosphere View Scheme

1.1: toluene-4-sulfonic acid / dichloromethane / 1 h / 20 °C / Inert atmosphere 2.1: isopropylmagnesium chloride / tetrahydrofuran / 0.58 h / -20 - -5 °C / Inert atmosphere 3.1: diethyl ether; hexane / 2 h / -78 - 20 °C / Inert atmosphere 4.1: potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / -78 °C / Inert atmosphere 4.2: 0.67 h / Inert atmosphere 5.1: toluene-4-sulfonic acid / methanol / 0.5 h / 20 °C / Inert atmosphere 6.1: tetrakis(triphenylphosphine) palladium(0); lithium chloride / diethyl ether / 0 °C / Inert atmosphere 6.2: 1 h / Inert atmosphere 7.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 0 °C / Inert atmosphere 8.1: sodium carbonate / N,N-dimethyl-formamide / 30 h / 80 °C / Inert atmosphere 9.1: lithium perchlorate; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 0.33 h / 20 °C / Molecular sieve; Inert atmosphere 10.1: osmium(VIII) oxide; water / tetrahydrofuran / 0.25 h / 0 °C / Inert atmosphere 10.2: 5 h / 0 °C / Inert atmosphere View Scheme

1.1: toluene-4-sulfonic acid / dichloromethane / 1 h / 20 °C / Inert atmosphere 2.1: isopropylmagnesium chloride / tetrahydrofuran / 0.58 h / -20 - -5 °C / Inert atmosphere 3.1: diethyl ether; hexane / 2 h / -78 - 20 °C / Inert atmosphere 4.1: potassium hexamethylsilazane / tetrahydrofuran; toluene / 0.5 h / -78 °C / Inert atmosphere 4.2: 0.67 h / Inert atmosphere 5.1: toluene-4-sulfonic acid / methanol / 0.5 h / 20 °C / Inert atmosphere 6.1: tetrakis(triphenylphosphine) palladium(0); lithium chloride / diethyl ether / 0 °C / Inert atmosphere 6.2: 1 h / Inert atmosphere 7.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 0 °C / Inert atmosphere 8.1: sodium carbonate / N,N-dimethyl-formamide / 30 h / 80 °C / Inert atmosphere 9.1: lithium perchlorate; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 0.33 h / 20 °C / Molecular sieve; Inert atmosphere 10.1: osmium(VIII) oxide; water / tetrahydrofuran / 0.25 h / 0 °C / Inert atmosphere 10.2: 5 h / 0 °C / Inert atmosphere 11.1: sodium tetrahydroborate / ethanol / 1 h / 0 - 20 °C / Inert atmosphere View Scheme

1: methyl 3-hydroxy-2-methylidene-propanoate With magnesium iodide in dichloromethane Cooling with acetone-dry iceInert atmosphere; 2: 2-iodo-propane With triethyl borane; tri-n-butyl-tin hydride in hexane; dichloromethane T=-78°C; 2.5 h; Inert atmosphere;

thionyl chloride 4 h; Heating;

1: 95 percent / 4 N aq. KOH / 8 h / Heating 2: 100 percent / SOCl2 / 4 h / Heating View Scheme