反应详情

To a flame-dried round-bottomed flask containing 6-[2'-(tert-butyl)dimethylsilyloxy-4'-bromo-5'-methoxyphenyl]methyl-5,5-dimethylcyclohex-2-en-1-one (13) (0.154 g, 0.454 mmol) in 22 mL ethyl acetate (which had been pre-dried over K2CO3) at room temperature was added 20 mg 5% palladium on carbon, and after flushing / evacuating the vessel 3 times with nitrogen, a hydrogen atmosphere was introduced and maintained by use of a balloon. After 24 h, the flask was again flushed several times with nitrogen, and the contents of the flask were filtered, rinsing with an additional 100 mL ethyl acetate. Rotary evaporation of the solvent afforded 0.156 g (quantitative) of the saturated benzylic ketone as a colorless, viscous oil (Rf 0.67, 2:1 hexanes/ethyl acetate). 1H NMR (400 MHz, CDCl3) δ0.22 and 0.25 [2s, 2×3H, Si(CH3)2 ], 0.87 and 1.12 (2s, 2×3H, geminal-CH3 's), 1.01 [s, 9H, SiC(CH3)3 ], 3.71 (s, 3H, OCH3), 6.79 (s, 1H, 6'-H), 6.91 ppm (s, 1H, 3'-H).

1. customafter flushing / evacuating the vessel 3 times with nitrogen
2. additiona hydrogen atmosphere was introduced
3. temperaturemaintained by use of a balloon
4. filtrationthe contents of the flask were filtered
5. washrinsing with an additional 100 mL ethyl acetate
6. customRotary evaporation of the solvent