1: 65 percent / tetrahydrofuran; diethyl ether / 1.) -78 deg C, 1 h; 2.) -20 deg C, 2.5 h 2: 44 percent Chromat. / hexane / 450 °C 3: hydrogen / 10 percent Pd-C / methanol / 760 Torr / Ambient temperature View Scheme

1: 65 percent / tetrahydrofuran; diethyl ether / 1.) -78 deg C, 1 h; 2.) -20 deg C, 2.5 h 2: 90 percent / lithium diisopropylamide, triethylamine / 1,2-dimethoxy-ethane / 0.25 h / 0 °C 3: 2.) 1 N hydrochloric acid / 1.) 425 deg C, n-hexane; 2.) methanol, room temperature, 30 min View Scheme

1.) THF, -78 deg C, 1 h., ; -20 deg C, 1 h., ; 0 deg C, 1 h., 2.) neat, 180 deg C, 45 min.; Yield given. Multistep reaction;