反应详情

Table 6 summarizes the results obtained on fluorination of 4-t-butyl cyclohexanone with the aminosulfur trifluorides. All of the compositions examined except N-naphthyl-N-phenylaminosulfur trifluoride converted the ketone to a mixture of 4-t-butyl-difluorocyclohexane and 4-t-butyl-1-fluorocyclohexene, with the former predominating. The fluorination of this ketone was much slower than observed for the fluorination of cyclooctanol. A complete conversion to the fluorinated products required several days at room temperature in CH2Cl2. However, addition of a catalytic amount of HF (generated in-situ from EtOH) accelerated the rate of reaction considerably. The reaction time was reduced from several days to ˜16 h when the diaryl, arylalkyl, and N-methoxyethyl-N-phenylaminosulfur trifluorides were reacted with 4-t-butylcyclohexanone in the presence of HF. The effect of HF on reaction rate was, however, less pronounced with the alkoxyalkyl aminosulfur trifluorides 37 and 41. A reasonable reaction time (40 h) for complete fluorination of the ketone with bis(methoxyethyl-aminosulfur trifluoride (41) was obtained when the reaction was carried out at 40° C.

1. customseveral days
2. customat room temperature
3. customthe rate of reaction considerably
4. waitThe reaction time was reduced from several days to ˜16 h
5. customThe effect of HF on reaction rate