Crystal and molecular structure of the germacrane furanosesquiterpenoid linderalactone

Abstract

The crystal structure of thetitle compound (I) has been determined by three-dimensional X-ray analysisfrom diffractometer data. Crystals are monoclinic, a= 8.804(1), b= 11.194(2), c= 6.630(1)Å, β= 105.6(2)°, Z= 2, space group P2₁. The structure was solved by direct methods and refined by full-matrix least-squares calculations to a final R of 0.064 for 941 independent observed reflexions. Hydrogen atoms were located from a difference-Fourier synthesis. The molecule consists of a furan, γ-lactone, and ten-membered ring. The conformation of the ten-membered ring was similar to those previously observed in several other germacrane sesquiterpenoids. The transannular separation in the ten-membered ring is distinctly short [C(1)⋯ C(4) 2.78 Å].