1: N-[(benzyloxy)carbonyl]-L-leucine With chloroformic acid ethyl ester; triethylamine in tetrahydrofuran; diethyl ether T=-25°C; 0.5 h; 2: diazomethane in tetrahydrofuran; diethyl ether T=-10 - 20°C; 3 h;

1: Et3N / diethyl ether; tetrahydrofuran / 0.5 h / -25 °C 2: diethyl ether / 3 h / -10 °C View Scheme

in diethyl ether; ethyl acetate T=2°C;

in diethyl ether T=-10°C; 3 h;