Methyl Benzoate → Adamantane

Participants

Reaction Steps

LiAlH4 (800 mg) was slowly added to a suspension of TiCl3 (THF)3 (16.5 g, 44.6 mmol) in anhydrous THF (15 ml) at 0° C. After 10 minutes at 0° C., triethylamine (3.5 ml) was added and the mixture was refluxed for one hour. A solution of 2-adamantanone 5 (822 mg, 5.47 mmol) and of the methyl benzoate ester 4b prepared previously (1.2 g, 444.50 mmol) in anhydrous THF (10 ml) was added dropwise to the mixture. The reaction mixture was refluxed for 3 hours. Water was added carefully to the mixture at 0° C., which was then diluted with diethyl ether. The organic phase was washed with a saturated solution of NaCl, then dried over MgSO4 and concentrated under reduced pressure. Chromatography on silica gel using cyclohexane/EtOAc (v/v:99/1) as eluent mixture made it possible to obtain 2-[1-(3-tert-butyldimethylsilyloxy)phenyl)-1-methoxy-methylene]tricyclo[3.3.1.1]decane 3b (796 mg, 66%) in the form of a colorless oil. 1H NMR (CDCl3, 300 MHz) δ 7.09 (t, 1H), 6.81 (d, 1H), 6.70 (m, 2H), 3.20 (s, 3H), 3.14 (br s, 1H), 2.54 (br s, 1H), 1.87-1.67 (m, 12H), 0.91 (s, 9H), 0.14 (s, 6H). 13C NMR (CDCl3, 75 MHz) δ 155.5, 143.6, 136.9, 131.2, 129.0, 122.6, 121.2, 119.5, 57.6, 39.3, 39.2, 38.9, 37.4, 32.9, 30.5, 25.8, 18.3, −4.70.

Provenance & Evidence