X-Ray structure analysis of the tosylate ester of (1S,5S)-6,6-dimethyl-2-[(2S)-3,3,3-trichloro-2-hydroxypropyl]bicyclo[3.1.1]hept-2-ene, the major product of the iron( III ) chloride-catalysed ene addition of chloral to (—)-(1S,5S)-pin-2(10)-ene

The crystal structure of the title compound (2) was determined by X-ray diffraction from diffractometer data by direct methods. Crystals are orthorhombic, space group P212121, with Z= 4 in a unit cell of dimensions: a= 13.076(4), b= 9.858(3), c= 16.234(4)Å; the structure was refined by full-matrix least-squares to R 0.0447, without recourse to weighting analysis, for 1.547 independent reflections. The correlation of the conformation of the pinene skeleton in (2) with the published crystallographic data for cis-pinocarvyl p-nitrobenzoate is good. Data are used for comment upon a published analysis of the 1H n.m.r. spectra of pinenes.