in N,N-dimethyl-formamide 1) -10 deg C, 1 h, 2) r.t., 2 d;

1: dicyclohexylcarbodiimide / dimethylformamide / -10 °C 2: 88 percent / dimethylformamide / 1) -10 deg C, 1 h, 2) r.t., 2 d View Scheme