sodium hydroxide in ethanol T=75 - 80°C; 10 h; further reag.: NaOMe in MeOH, 95 deg C, 3 d;

in water T=70°C; 48 h; also from chloroacetaldehyde diethylacetal;

1: 94 percent / NH4OAc / dimethylformamide / 2 h / 80 - 85 °C 2: 72 percent / 3M NaOH / ethanol / 10 h / 75 - 80 °C / further reag.: NaOMe in MeOH, 95 deg C, 3 d View Scheme

1: 1) dibutyltin oxide, 2) Et3N / 1) MeOH, 30 min, reflux, 2) acetone, 10 min 2: 94 percent / NH4OAc / dimethylformamide / 2 h / 80 - 85 °C 3: 72 percent / 3M NaOH / ethanol / 10 h / 75 - 80 °C / further reag.: NaOMe in MeOH, 95 deg C, 3 d View Scheme

1: 56 percent / MCPBA / acetic acid / 18.5 h / Ambient temperature 2: 72 percent / 3M NaOH / ethanol / 10 h / 75 - 80 °C / further reag.: NaOMe in MeOH, 95 deg C, 3 d View Scheme