1.1: dicyclohexyl-carbodiimide; 1-hydroxy-pyrrolidine-2,5-dione / dichloromethane / 1 h / 20 °C 1.2: 1 h / 20 °C 1.3: 0.5 h 2.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / N,N-dimethyl-formamide; acetonitrile / 0.25 h / 20 °C View Scheme

1.1: dicyclohexyl-carbodiimide; 1-hydroxy-pyrrolidine-2,5-dione / dichloromethane / 1 h / 20 °C 1.2: 1 h / 20 °C 1.3: 0.5 h 2.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / N,N-dimethyl-formamide; acetonitrile / 0.25 h / 20 °C View Scheme