1: 1.) sulfur trioxide-pyridine complex, Et3N, 2.) aq. NaClO2, 2-methyl-2-butene, NaH2PO4*2H2O / 1.) DMSO, RT, 1 h, 2.) t-BuOH, RT, 18 h 2: diethyl ether 3: H2 / Pd(OH)2 / ethanol / Ambient temperature 4: camphorsulphonic acid / benzene / 1 h / Heating View Scheme