A new tetrasubstituted α-fluoro cyclohexanone bearing a fluoroisopropyl group at C5

A new tetrasubstituted cyclohexanone 5 fluorinated at C2 and having a fluoroisopropyl group at C5 has been synthesized in five steps from 3-methyl cyclohexenone and the structure of both diastereomers fully assigned. It is shown that diastereomer Ia having the fluorine atom at C2 in the axial position (in the most populated conformer of this diastereomer) is major and is a good catalyst for epoxidation of trans-olefins by oxone while diastereomer IIe is not. Moreover, only 0.3 equiv. of 5-Ia are necessary and the ketone is totaly recovered after reaction (no Baeyer–Villiger).

Diastereomer 5-Ia of difluorinated ketone 5 is easily synthesized in five steps and 43% overall yield and is an efficient catalyst for epoxidation of trans-olefins with oxone. It is also shown that diastereomer 5-IIe with the fluorine at C2 equatorial is not a catalyst for epoxidation. Figure optionsDownload as PowerPoint slide