VALPARANE, A NEW DITERPENE SKELETON .4. ABSOLUTE STEREOCHEMISTRY OF VALPARONE, VALPAROLONE AND OTHER COMPOUNDS WITH VALPARANE SKELETON

The unsaponificable part of the hexane extract of Halimium viscosum chemotype (Valparaiso, Zamora, Spain) afforded three hydrocarbons, an epoxide, a ketone (valparone), five allylic alcohols and a seco derivative with valparane skeleton and an alpha,beta-unsaturated ketone with valparolane skeleton. The majority of them have been correlated chemically. Chemical correlation between valparanes and valparolanes, absolute stereochemistry determined by means of CD for valparone and the confirmation of the absolute stereochemistry of valparanic and valparolanic compounds have been done by CD curve of the cyclohexanone obtained from valparolone.