1: With mercaptoacetic acid; triethylamine in dichloromethane T=0°C; 0.5 h; 2: With sodium carbonate in dichloromethane; water T=20°C; 0.5 h;

1.1: mercaptoacetic acid; triethylamine / dichloromethane / 0.5 h / 0 °C 1.2: 0.5 h / 20 °C 2.1: sodium tetrahydroborate / methanol / 20 °C 3.1: boron tribromide / dichloromethane / 0.17 h / 20 °C View Scheme

1.1: mercaptoacetic acid; triethylamine / dichloromethane / 0.5 h / 0 °C 1.2: 0.5 h / 20 °C 2.1: sodium tetrahydroborate / methanol / 20 °C View Scheme

1: With mercaptoacetic acid; triethylamine in dichloromethane T=0°C; 0.5 h; 2: With sodium carbonate in dichloromethane; water T=20°C; 0.5 h;