1: 46.5 percent / D-dibenzoyl tartaric acid/CH2Cl2 / ethanol 2: 73 percent / NaOH / ethanol; H2O / 1.5 h / Heating 3: 73 percent / decahydronaphthalene / 2 h / 180 °C / Heating 4: 98 percent / NaOCH3 / methanol / 2 h / Heating 5: 90 percent / H2O; HCl / 0.5 h / 80 °C / Heating View Scheme

1: 46.5 percent / D-dibenzoyl tartaric acid/CH2Cl2 / ethanol 2: 83 percent / ethanol; H2SO4 / 0.5 h / Heating View Scheme

1: 46.5 percent / D-dibenzoyl tartaric acid/CH2Cl2 / ethanol 2: 75.8 percent / NaOCH3 / methanol / 4 h / Heating 3: 1.) 5percent aq.H2SO4; 2.) NaOMe / 1.) AcOH, heating, 2 h; 2.) MeOH, rt, 2 h View Scheme