1: 68.5 percent / DCC; DMAP / tetrahydrofuran / 12 h / 25 °C 2: 96 percent / dimethyl dioxirane / acetone / 0.08 h / 0 °C 3: 88 percent / aq. sodium phosphate buffer / acetonitrile / 48 h / 37 °C / pH 7.5 View Scheme

triethylamine in tetrahydrofuran T=25°C; 24 h;

2 h; Heating;