1: With chloro-trimethyl-silane; 1,1,1-triethoxyethane in dichloromethane T=0°C; 2 h; 2: With potassium carbonate in methanol T=20°C; 2 h;

1.1: 91 percent / AD-mix-α / 2-methyl-propan-2-ol; H2O / 5 h / 0 °C 2.1: triethyl orthoacetate; trimethylsilyl chloride / CH2Cl2 / 2 h / 0 °C 2.2: 92 percent / K2CO3 / methanol / 2 h / 20 °C View Scheme