The molecular and crystal structures of chiral 1R,4R-cis-2-(4-phenylbenzyli
dene)-n-menthan-3-one (I) have been determined by X-ray diffraction analysi
s. Crystals I are monoclinic, a = 6.755(3) Angstrom, b = 9.860(3) Angstrom,
c = 14.103(6) Angstrom, beta = 98.95(1)degrees, space group P2(1), Z = 2,
and R = 0.035 for 1031 reflections. A chair conformation of the cyclohexano
ne ring in the molecule is substantially distorted toward a "half-chair" co
nformation. The enone and benzylidene groupings are virtually planar (the t
orsion angles are equal to 13.0 degrees and 4.9 degrees respectively). The
benzene rings of the biphenyl fragment are rotated with respect to each oth
er through an angle of 40 degrees -43 degrees. Among the compounds under co
nsideration, the distortion of bond angles at the sp(2) carbon atoms of the
benzylidene grouping as a criterion for the steric stress of molecules is
maximum in structure I. (C) 2001 MAIK "Nauka/Interperiodica".