Facile access to optically active ring C aromatic diterpene derivatives from (+)-manool. first synthesis of 13,14-dihydroxy8,11,13-podocarpatrien-7-one.

14,15,17-Trinorlabdan-8,13-dione 6 was efficiently synthesized via ozonolysis of (+)-manool (4) followed by treatment with aqueous NaOH in the presence of tetra-n-butylammonium bromide as catalyst. This protocol has the advantages of high yield, mild conditions and simple procedure. Utilizing this strategy, the first enantiospecific synthesis of 13,14-dihydroxy-8,11,13-podocarpatrien-7-one (1), a constituent of Taiwania cryptomerioides and Celastrus paniculatus, was achieved starting from (+)-manool (4) after a four-step sequence in 24% overall yield.