molecular sieve in dichloromethane 2 h; Ambient temperature;

1: 72 percent / n-amyl nitrite, conc. HCl / ethanol / 1) 50 deg C, 2 h 2: 78 percent / sodium borohydride / ethanol / 24 h / 23 °C 3: 61 percent / p-toluene-sulfonyl chloride / pyridine / 2.5 h / Ambient temperature 4: 77 percent / molecular sieves / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: 78 percent / sodium borohydride / ethanol / 24 h / 23 °C 2: 61 percent / p-toluene-sulfonyl chloride / pyridine / 2.5 h / Ambient temperature 3: 77 percent / molecular sieves / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: 61 percent / p-toluene-sulfonyl chloride / pyridine / 2.5 h / Ambient temperature 2: 77 percent / molecular sieves / CH2Cl2 / 2 h / Ambient temperature View Scheme