oxalic acid in tetrahydrofuran; water T=20°C; 4 h;

methanesulfonic acid; tributylphosphine; N-benzyl-N,N,N-triethylammonium chloride in dichloromethane T=0°C; electrolysis; Yields of byproduct given;

1.1: i-PrNH2; BuLi / tetrahydrofuran; hexane / 1 h / 0 °C 1.2: 68 percent / hexane; tetrahydrofuran; hexamethylphosphoric acid triamide / 1 h / 0 °C 2.1: (CO2H)2*2H2O / tetrahydrofuran; H2O / 4 h / 20 °C View Scheme