A 500 mL three-neck flask was fitted with a reflux condenser, 125 mL addition funnel, and nitrogen line. The apparatus was dried by means of a hot air gun and nitrogen purging. Dry THF (200 mL) was added and the flask cooled in an ice bath. TiCL3 (24 g, 156 mmol) was added rapidly followed by LAH (2.8 g, 75 mmol) in portions with stirring. The cooling bath was removed and the black mixture was allowed to warm to room temperature. Triethylamine (12 mL, 86 mmol) was added to the stirred suspension and refluxed for 1 hour. After this period a solution of methyl 3-tert-butyldimethylsilyloxybenzoate (4.40 g, 16.6 mmol) and 2-adamantanone (3.0 g, 20.4 mmol) in 50 mL of dry THF was added dropwise to the refluxing mixture over 5 hours. Refluxing was continued for an additional 4 hours after which the reaction was cooled to room temperature and diluted with 100 mL of ether. The organic solution was separated and concentrated. Chromatography over silica with 1% ethyl acetate/hexane gave 1.29 g (21%) of 7b as an oil: 1H NMR (CDCl3) delta 0.196 (s, 6H), 0.985 (s, 9H), 1.78-1.97 (m, 12H), 2.628 (s, 1H, 3.23 (s, 1H), 3.29 (s, 3H), 6.75-7.20 (m, 4H); 13C NMR (CDCl3) delta -4.50, 18.19, 25.67, 28.37, 30.16, 32.28, 37.25, 38.19, 39.01, 57.51, 119.29, 121.08, 122.32, 128.87, 131.11, 136.84, 143.47, 155.37. ##STR45## Preparation of 1,2-Dioxetanes
