chloro-trimethyl-silane; Pd(OAc)2*PPh3; potassium carbonate in toluene T=140°C; Carbonylation; cyclization; 24 h;

1: SOCl2 / benzene / 20 °C 2: dimethylsulfoxide; benzene / 2 h 3: 92 percent / 4N NaOH / ethanol / 20 h / Heating 4: SOCl2 / benzene / 2 h / 50 - 60 °C 5: 91 percent / benzene; pyridine / 20 °C 6: 85 percent / POCl3 / toluene / 3 h / Heating 7: 100 percent / NaBH4 / methanol / 0.25 h 8: 75 percent / Pd(OAc)2; PPh3; K2CO3 / toluene / 26 h / Heating 9: 87 percent / LiAlH4 / tetrahydrofuran / 0.75 h / Heating View Scheme

1: 1.) NaH / 1.) DMF, 0 deg C, 2.) rt, 3 h 2: 1.) t-BuLi, 2.) methanol / 1.) THF, pentane, -100 to -95 deg C, 30 min, 2.) rt 3: methanol, trifluoroacetic acid / tetrahydrofuran; pentane / 36 h / Ambient temperature View Scheme

chloro-trimethyl-silane; Pd(OAc)2*PPh3; potassium carbonate in toluene T=140°C; Carbonylation; cyclization; 24 h;

n-butyllithium; carbon dioxide 1.) THF, -78 deg C, 1 min; 2.) THF, 10 min; Yield given. Multistep reaction. Yields of byproduct given;

n-butyllithium 1.) THF, -78 deg C, 1 min; 2.) THF, 10 min; Yield given. Multistep reaction. Yields of byproduct given;

chloro-trimethyl-silane; Pd(OAc)2*PPh3; potassium carbonate in toluene T=140°C; Carbonylation; cyclization; 24 h;

n-butyllithium; carbon dioxide 1.) THF, -78 deg C, 1 min; 2.) THF, 10 min; Yield given. Multistep reaction. Yields of byproduct given;

n-butyllithium 1.) THF, -78 deg C, 1 min; 2.) THF, 10 min; Yield given. Multistep reaction. Yields of byproduct given;

sodium tetrahydroborate in tetrahydrofuran; methanol Reduction; 2 h;