Synthesis of (3S,4R)-(+)-hydroxymethyl-3-(trifluoromethyl)-4,5,5-trimethylcyclopentene — a trifluoromethyl analogue of necrodols

New trifluoromethyl group containing enantiomerically pure monoterpene derivatives, methyl (1S,3R,4S)-(+)-4-(trifluoromethyl)-2,2,3-trimethylcyclopentanecarboxylate (6); methyl (3S,4R)-(+)-3-(trifluoromethyl)-4,5,5-trimethylcyclopentenecarboxylate (10) and (3S,4R)-(+)-hydroxymethyl-3-(trifluoromethyl)-4,5,5-trimethylcyclopentene (1), were prepared using camphoric anhydride as the starting material and sulphur tetrafluoride as the fluorinating agent. Compound 1 is a trifluoromethyl analogue of an unknown isomer of necrodols.