N,N-diisopropylamine tetrazolide in dichloromethane 2 h;

1: 73 percent / 1H-tetrazole / CH2Cl2 / 2 h / Ambient temperature 2: 1H-tetrazole / tetrahydrofuran / 1.5 h / Ambient temperature 3: 80percent mCPBA / tetrahydrofuran / 0.67 h / 0 - 20 °C 4: 80.9 percent / 90percent aq. AcOH, Zn / 1.5 h View Scheme

1: 73 percent / 1H-tetrazole / CH2Cl2 / 2 h / Ambient temperature 2: 1H-tetrazole / tetrahydrofuran / 1.5 h / Ambient temperature 3: 80percent mCPBA / tetrahydrofuran / 0.67 h / 0 - 20 °C 4: 86 percent / 90percent aq. AcOH, Zn / 1.5 h View Scheme

1: 2,4-dinitrophenol / CH2Cl2 / 2 h 2: t-BuOOH / decane / -78 °C View Scheme