1: 96 percent / toluene-p-sulphonic acid / acetone; H2O / 20 h / 20 °C 2: 87 percent / aqueous potassium hydroxide / methanol 3: 1.) boron trichloride / 1.) dichloromethane, -78 deg C, 1 h, 2.) methanol, - 78 deg C -> room temperature 4: 51 mg / H2 / 5percent Pd-C / ethyl acetate 5: 33 percent / sodium borohydride / methanol / 3 h View Scheme

1: 96 percent / toluene-p-sulphonic acid / acetone; H2O / 20 h / 20 °C 2: 87 percent / aqueous potassium hydroxide / methanol 3: 1.) boron trichloride / 1.) dichloromethane, -78 deg C, 1 h, 2.) methanol, - 78 deg C -> room temperature 4: 51 mg / H2 / 5percent Pd-C / ethyl acetate View Scheme

1: 96 percent / toluene-p-sulphonic acid / acetone; H2O / 20 h / 20 °C 2: 87 percent / aqueous potassium hydroxide / methanol 3: 1.) boron trichloride / 1.) dichloromethane, -78 deg C, 1 h, 2.) methanol, - 78 deg C -> room temperature 4: 51 mg / H2 / 5percent Pd-C / ethyl acetate 5: 7 percent / sodium borohydride / methanol / 3 h View Scheme