From natural camphor to (1R,2S)-2-chloromethyl-3-oxocyclopentanecarboxylicacid: a stereocontrolled approach to enantiopure sarkomycin

The preparation of enantiopure (1R,2S)-2-chloromethyl-3-oxocyclopentanecarb oxylic acid 9. an interesting possible precursor of the antitumor agent sar komycin, from a camphor-derived 3-hydroxymethylorbornan-2-one is reported. The described procedure Constitutes the fil-st stereocontrolled approach to sarkomycin starting from commercially available natural camphor. The proce dure takes place in only six steps with a high overall yield (59%). The key -step of the described procedure is the stereocontrolled ring opening of a conveniently functionalized 3-oxonorborn-1-yl triflate under a straightforw ard basic hydrolysis. The described route constitutes a model procedure for the preparation of other enantiopure C2-substituted 3-oxocyclopentanecarbo xylic acids, which are related with the sarkomycin family of antitumor agen ts. (C), 2001 Elsevier Science Ltd. All rights reserved.