Tri- and tetrasubstituted alpha-fluorocyclohexanones with enantiomeric excesses in the range of 97-100%

The alpha -fluorinated trisubstituted ketones (2S,5R)-(-1-7-Ia. (2R,5R)-(+) -7-IIe. (2S,5R)-(-)-8-Ia and (2R.5R)-(+)-8-IIe were synthesised from (+)-di hydrocarvone (99%, (R)-configuration at C-5) and fully characterised. alpha -Fluorinated tetrasubstituted ketones (-)-9-Ia, (+)-9-Ia, (+)-9-IIa and ()-10-Ia having e.e.s of greater than or equal to 97% were synthesised as ra cemates from 3-methyl cyclo-hexenone then resolved into the pure enantiomer s using chiral HPLC and fully characterised. (C) 2001 Published by Elsevier Science Ltd.