lithium hydroxide; mercaptoacetic acid in N,N-dimethyl-formamide T=20°C; 2.5 h;

lithium aluminium tetrahydride in tetrahydrofuran T=0 - 5°C; 0.75 h;

1: 85.3 percent / lithium aluminium hydride / tetrahydrofuran / 0.75 h / 0 - 5 °C 2: 96.6 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 2.5 h / Ambient temperature View Scheme