Semisynthesis of (+)-angeloyl-gutierrezianolic acid methyl ester diterpenoid

This paper describes the use of zamoranic acid in the first semisynthesis of the furolabdane (+)-angeloyl-gutierrezianolic acid methyl ester diterpenoid, which also establishes the absolute configuration of the natural product. Direct deconjugation of Δ7 in zamoranic acid and Bestmann methodology for the furan ring synthesis are the key steps.