反应详情

A solution of 2-methyl-2-phenyl-cyclohexanone (0.94 g, 5.0 mmol) in chloroform (12 mL) at −5° C. was treated via rapid dropwise addition with a solution of bromine (0.26 mL, 5.1 mmol) in chloroform (6 mL) so as the reaction temperature maintaining below 5° C. The solution was kept at 0° C. for 2 h when the red color had disappeared. The mixture was concentrated under reduced pressure to give the crude title compound (1.35 g, 100%) as a brown oil which was used directly in the next step. MS ISP (m/e): 267.3 [(M+H)+]. 1H NMR (DMSO-D6, 300 MHz): δ (ppm)=7.22-7.42 (m, 3H), 7.13 (d, 2H), 4.70 (dd, 1H), 2.75 (m, 1H), 2.52 (m, 1H), 1.7-2.4 (m, 4H), 1.36 (s, 3H).

1. temperaturemaintaining below 5° C
2. concentrationThe mixture was concentrated under reduced pressure