Constituents of Solidago Species. Part V. Non-acidic Diterpenoids from Solidago gigantea var. serotina

Abstract

Eight new furan-containing diterpenoids from Solidago gigantea Ait. var. serotina (Kuntze) Cronqu., are formulated as 1c–g, 2, 3a, and 4a on the basis of chemical and spectroscopic evidence and by correlation with solidagoic acid A of previously defined constitution and stereochemistry. The structure (5a) of a ninth related compound is tentatively assigned. The allylic oxidation of some of these new diterpenoids and related compounds with the chromium trioxide – pyridine complex is reported. In the course of this investigation of formal total synthesis of compound Y from Leonotis leonurus was achieved.