Total syntheses of the tetracyclic furanoid diterpenes methyl vinhaticoate (1) and methyl vouacapenate (2) are described. These syntheses of racemic 1 from the previously described intermediate 4 and of natural (+)-2 from podocarpic acid (3) required solution of two key problems. First, the secondary methyl group at CH had to be introduced with known stereochemistry so that the previously undefined configuration at that center could be determined to be a, as shown in 1 and 2. Second, a new method for elaboration of the furan moiety had to be developed. Treatment of 2-methoxymethylene ketones 28 and 47 with ethyl diazoacetate in the presence of copper sulfate was found to lead to furoic esters 29 and 48 which could readily be converted to the natural products.

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Phyllocladene, (+)-rirnuene, (+)-isokaurene, (-)-sandaracopirnaradiene, and (+)-rnanoyl oxide have been identified in the diterpenoid fraction of the oil, which contains in addition a new diterpene alcohol, which has been shown to be (-) -8 p-hydroxy-sandaracopimar-15-ene.THE diterpene fraction of the volatile oil of D. colensoi diterpene fraction remaining after the isolation of has been examined by Briasco and Murray,l who isolated phyllocladene and isophyllocladene by Briasco and (+)-phyllocladene and (-)-isophyllocladene, and by Murray was the subject of the investigation reported Aplin, Cambie, and Rutledge,2 who by gas-liquid in this Paper. chromatography showed the presence of the same two Hydrocarbon and oxygenated hydrocarbon fractions diterpenes, and in addition the diterpene rimuene. The were separated by alumina chromatography. Thin-1