Regioselective Synthesis of Polyfluoroalkyl Substituted 6,7‐Dihydrobenzisoxazolones

摘要

> Regioselective methods for synthesis of hitherto unreported both 6,7‐dihydro‐1,2‐benzisoxazol‐4(5 H )‐ones and 6,7‐dihydro‐2,1‐benzisoxazol‐4(5 H )‐ones with perfluoroalkyl or halogenodifluoromethyl substituents have been developed. 3‐Polyfluoroalkyl‐6,7‐dihydro‐1,2‐benzisoxazol‐4(5 H )‐ones were prepared by the cyclocondensation of 2‐polyfluoroalkanoylcyclohexane‐1,3‐diones with hydroxylamine. The regioisomeric 3‐polyfluoroalkyl‐6,7‐dihydro‐2,1‐benzisoxazol‐4(5 H )‐ones were synthesized by the transformation of 2‐polyfluoroalkanoylcyclohexane‐1,3‐diones into their vinylogous chlorides, followed by the interaction of obtained crude 3‐chloro‐2‐polyfluoroalkanoyl‐2‐cyclohexen‐1‐ones with sodium azide in dimethylformamide.