Oxidation with lead tetraacetate has been found to be a useful tool for the syntheses of novel type of longifolane derivatives without ring re-arrangement. Isolongifolol (VIII) on treatment with lead tetraacetate in benzene solution is converted to isolongifolanoxide (IX), further oxidation of which with chromic acid yields isolongifolanolide (X). The structure of this lactone is consistent with the spectral data and the Hudson-Klyne lactone rule. The ...
