1.1: n,N-diisopropylethylamine / CHCl3 / 20 °C 2.1: 693 mg / NaOMe / methanol / 3 h / Heating 3.1: 97.1 percent / PPh3; DEAD / toluene / 20 °C 4.1: NaOMe / methanol / Heating 4.2: 89 percent / aq. AcOH / 100 °C View Scheme

1.1: SO3*pyridine; Et3N / dimethylsulfoxide / 3 h / 20 °C 2.1: 433 mg / NaBH4 / methanol; CH2Cl2 / 2.5 h / 20 °C 3.1: NaOMe / methanol / 1.5 h / Heating 3.2: 92 percent / aq. AcOH / 3 h / 100 °C View Scheme