triethylamine in N,N-dimethyl-formamide T=0°C; 18 h;

n-butyllithium; chloro-trimethyl-silane; 4-toluenesulfonyl azide; triphenylemethane; diisopropylamine in tetrahydrofuran 1) -78 deg C, 40 min; 2) R.T. 1 h;

1: 65 percent / 1) n-BuLi, triphenylmethane, diisopropylamine; 2) p-toluenesulfonyl azide, trimethylsilyl chloride / tetrahydrofuran / 1) -78 deg C, 40 min; 2) R.T. 1 h 2: 64 percent / 48percent HF / various solvent(s) / 6.5 h View Scheme

1: 65 percent / 1) n-BuLi, triphenylmethane, diisopropylamine; 2) p-toluenesulfonyl azide, trimethylsilyl chloride / tetrahydrofuran / 1) -78 deg C, 40 min; 2) R.T. 1 h 2: 64 percent / 48percent HF / various solvent(s) / 6.5 h 3: 95 percent / 1) H2; 2) HCO2H / 10percent Pd/C / methanol / 1) 20 min; 2) 1 h, 5 deg C View Scheme