Brevione A

(2S,4a′R,4b′R,8a′R,10a′R)-2′,4b′,6,7,8′,8′,10a′-Heptamethyl-4a′,5′,6′,8′,8a′,9′,10′,10a′-octahydro-3H,4H,4′H-spiro[furo[3,2-c]pyran-2,1′-phenanthrene]-4,7′(4b′H)-dione

Brevione A

Spiro[4H-furo[3,2-c]pyran-2(3H),1′(4′H)-phenanthrene]-4,7′(6′H)-dione, 4′a,4′b,5′,8′,8′a,9′,10′,10′a-octahydro-2′,4′b,6,7,8′,8′,10′a-heptamethyl-, (2S,4a′R,4b′R,8a′R,10a′R)-

(+)-brevione B