X-ray investigations of stereochemical problems: an X-ray crystal-structure analysis of 2α, 10-dibromo-10β-pinan-3-one (1967)
AuthorsJameson, M. B.show all
The crystal structure of the 2,10-dibromo-10 β-pinan-3-one, a bromo derivative of the naturally occurring β-pinene, has been determined by X-ray analysis. The compound crystallized in the unusual trigonal space group P3₁, with three molecules in the unit cell of dimensions 20.3 x 20.3 x 7.00 Å. The structure has confirmed the distorted nature of the pinnae skeleton compared with cyclohexanone, the buckled cyclobutane ring, and the correctness of the structure assignment made by Wallis. An essentially planar conformation has been found rather than the more usual up or down conformations expected in six-membered hydrocarbons. The molecular geometry is discussed and compared with other recent structures which have been reported in the previously unexplored pinane field. The thesis also describes an examination of the effect of anomalous dispersion and in an appendix the development of a computer program to handle the process both densitometer and visually estimated reflection data from Weissenberg photographs.