(4’R,4a’S,7a’R,12b’S)-3′-allyl-1′,2′,3′,4′,5′,6′-hexahydro-4a’H,7a’H-spiro[[1,3]dioxolane-2,7′-[4,12]methanobenzofuro[3,2-e]isoquinoline]-4a’,9′-diol