反应详情

A solution of sodium bromide (6.17 g) in water (10 ml) and commercial bleach (31.2 ml of a solution of sodium hypochlorite) were stirred together for 5 minutes and a solution of dihydro-α-ionone (3.88 g) in methylene chloride was added. Then a solution of potassium phosphate (monobasic) (5.44 g) in water (30 ml) was added during 30 minutes. After stirring for 50 minutes at 25° a solution of sodium bromide (2.05 g) and commercial bleach (10 ml) was added, followed by a solution of potassium phosphate (monobasic) (2.72 g) in water (10 ml) and the reaction mixture stirred for 15 minutes at 25°. The methylene chloride solution was washed with sodium bicarbonate solution and the solvent evaporated to provide the crude product (5.86 g). Column chromatography gave 1.87 g of 4-(5-bromo-6-methylene-2,2-dimethylcyclohexyl)-2-butanone. NMR (CDCl3) δ0.93 (6H, s, >C(CH3)2), 0.9-2.6 (9H, m), 2.12 (3H, s, --COCH3), 4.6-5.1 (1H, m, >CHBr), 4.76 and 5.28 (2H, 2s, >C=CH2), 4.68 and 5.20 (2H, 2s, >C=CH2, minor isomer; isomer ratio 3/1). IR (film) νmax 2960, 1720, 1675, 1650, 1455, 1360.

1. additionwas added
2. washThe methylene chloride solution was washed with sodium bicarbonate solution
3. customthe solvent evaporated
4. customto provide the crude product (5.86 g)