Constituents of Solidago Species. Part VI. The Constitution of Diterpenoids from a Chemically Distinct Variety of Solidagoserotina

Abstract

One known (1) and eight new (3, 5, 6a, 7, 8a, 15, 16, and 19b) diterpenoids have been isolated from a chemically distinct subgroup within the species Solidagoserotina Ait. The constitution and stereochemistry of the new compounds are deduced from their spectroscopic properties and chemical reactions. Of key importance are the conversions of (i) 6a and 8a into 8b, which has been synthesized from methyl kolavenate (9); (ii) 1 and 15 into 3; and (iii) 15 and 19b into 16. Also discussed are the cleavages of the epoxides 10 and 15 with boron trifluoride which result in rearrangement, the products being 12 and a mixture of 16, 17a, and 17b, respectively.