sodium tetrahydroborate in tetrahydrofuran; diethyl ether; ethanol T=20°C; Dimerization; 1 h;

1: 95 percent / HBF4; i-C5H11ONO / ethanol / 0.5 h 2: 37 percent / dimethylformamide / 20 °C 3: 92 percent / NaBH4; air / diethyl ether; tetrahydrofuran; ethanol / 1 h / 20 °C View Scheme

1: Cu / dimethylsulfoxide / Heating 2: 95 percent / HBF4; i-C5H11ONO / ethanol / 0.5 h 3: 37 percent / dimethylformamide / 20 °C 4: 92 percent / NaBH4; air / diethyl ether; tetrahydrofuran; ethanol / 1 h / 20 °C View Scheme

1: Cu / dimethylsulfoxide / Heating 2: 95 percent / HBF4; i-C5H11ONO / ethanol / 0.5 h 3: 37 percent / dimethylformamide / 20 °C 4: 92 percent / NaBH4; air / diethyl ether; tetrahydrofuran; ethanol / 1 h / 20 °C View Scheme