55058-60-1 (E)-2-Methyl-2-butenoic acid [(4S)-4,4a,5,6,7,8,8aα,9-octahydro-8α-hydroxy-3,4aβ,5β-trimethyl-9-oxonaphtho[2,3-b]furan-4β-yl] ester 55058-61-2 (Z)-2-Methyl-2-butenoic acid [(4S)-8α-acetoxy-4,4a,5,6,7,8,8aα,9-octahydro-3,4aα,5β-trimethyl-9-oxonaphtho[2,3-b]furan-4β-yl] ester