Crystal structure of syn-8,8-dichloro-4-phenyl-3,5-dioxabicyclo[5,1,0]octane

Abstract

The crystal and molecular structure of the title compound has been determined from three-dimensional X-ray diffraction data. Crystals are monoclinic, space group P2₁/c, with Z= 8 in a unit cell of dimensions a= 21·231(6), b= 6·047(2), c= 19·408(5)Å, and β= 106·90(2)°. The structure was solved by direct methods and refined by least-squares techniques to R 0·089 for 1672 observed reflections obtained by diffractometer. The two molecules in the asymmetric unit have nearly identical geometries, with the seven-membered ring in the chair conformation. The phenyl group is equatorial and the dichloromethylene group is oriented to give the syn-isomer. The addition of the dihalogenocarbene to the parent olefin appears to be sterically rather than electronically controlled. The distances and angles in the molecule are as expected.