anhydrous guanidine in methanol T=0°C; Substitution; Mitsunobu inversion; 0.25 h;

1.1: guanidine / methanol / 0.25 h / 0 °C 2.1: 88 percent / Et3N / tetrahydrofuran / 20 °C 3.1: n-BuLi; CuCN; MeLi / diethyl ether / 3.08 h / -78 - 0 °C 3.2: diethyl ether; hexane / 0.33 h / -78 °C 4.1: pyridinium p-toluenesulfonate / acetone; H2O / 4 h / 20 °C 5.1: 89 percent / porcine pancreatic lipase; NaCl; CaCl2 / H2O; tetrahydrofuran / 0.5 h / Enzymatic reaction; pH 7.1 View Scheme

1: guanidine / methanol / 0.25 h / 0 °C 2: 88 percent / Et3N / tetrahydrofuran / 20 °C View Scheme