Crystal and molecular structure of goniothalamin [(+)-(6S)-5,6-dihydro-6-styryl-2-pyrone]

Abstract

The crystal structure of goniothalamin has been determined from three-dimensional X-ray diffraction data. Crystals are monoclinic, with a= 9·710(3), b= 9·967(5), c= 5·691(3)Å, β= 98·72(3)°, Z= 2, space group P2₁. The structure was solved by direct methods and refined by full-matrix least-squares to R 0·040 for 789 observed reflections. The planar styryl group adopts a pseudo-equatorial position on the lactone ring, and is inclined at 88·1° to the mean plane of it. The ester group of the unsaturated lactone is non-planar, and the lactone ring has a modified skew-boat conformation.