trifluoroacetic acid in tetrahydrofuran T=0°C;

2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine in dimethyl sulfoxide T=20°C; regioselective reaction;

1: oxalyl chloride / benzene / 1 h / Heating 2: pyridine / 60 °C 3: aq. TFA / tetrahydrofuran / 0 °C View Scheme

1: pyridine / 60 °C 2: aq. TFA / tetrahydrofuran / 0 °C View Scheme

1: hydrogen; ethylenediamine / ethanol; water 2: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine / dimethyl sulfoxide / 20 °C View Scheme

1.1: n-butyllithium / tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide; hexane / 0.5 h / -60 °C 1.2: -20 - 20 °C 2.1: Jone's reagent / acetone / 0 - 4 °C 3.1: sulfuric acid / 20 °C 4.1: hydrogen; ethylenediamine / ethanol; water 5.1: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine / dimethyl sulfoxide / 20 °C View Scheme

1: sulfuric acid / 20 °C 2: hydrogen; ethylenediamine / ethanol; water 3: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine / dimethyl sulfoxide / 20 °C View Scheme

1.1: toluene-4-sulfonic acid / dichloromethane / 20 °C 2.1: n-butyllithium / tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide; hexane / 0.5 h / -60 °C 2.2: -20 - 20 °C 3.1: Jone's reagent / acetone / 0 - 4 °C 4.1: sulfuric acid / 20 °C 5.1: hydrogen; ethylenediamine / ethanol; water 6.1: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine / dimethyl sulfoxide / 20 °C View Scheme

1: Jone's reagent / acetone / 0 - 4 °C 2: sulfuric acid / 20 °C 3: hydrogen; ethylenediamine / ethanol; water 4: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine / dimethyl sulfoxide / 20 °C View Scheme