1: 1.) trimethyloxonium tetrafluoroborate, 2.) aq. NaOH / 1.) CH2Cl2, RT, 2 h, 2.) CH2Cl2, 2.5 h 2: 1.) n-butyllithium, 2.) BF3*OEt2 / 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, -78 deg C, 1.5 h 3: 92 percent / H2, quinoline / Lindlar catalyst / ethyl acetate / 760 Torr 4: 89 percent / p-TsOH, water / toluene / 1.5 h / Heating View Scheme

sodium hydroxide; trimethyl-oxonium tetrafluoroborate 1.) CH2Cl2, RT, 2 h, 2.) CH2Cl2, 2.5 h; Yield given. Multistep reaction;