First total synthesis of naturally occurring (-)-nitidon and its enantiomer

The first total synthesis of naturally occurring (-)-nitidon and its enantiomer is reported. The best of the routes investigated for preparation of these enantiomerically pure compounds involves a modification of the Cadiot-Chodkiewicz reaction and the Sharpless asymmetric epoxidation of an (E)-2-ene-4,6-diyn-1-ol as key steps and proceeds in five steps and 18% overall yield. Both enantiomers of nitidon and some related 6-(1,3-diyn-1-yl)-2H-pyran-2-ones have been found to exhibit significant cytotoxic activity against human cancer cell lines in vitro. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).