4-Cyano-4'-[(4R)-4,5-epoxypentyloxy]biphenyl: a Pseudosymmetry Problem Solved with Synchrotron Data

The title compound, 4'-[(4R)-4,5-epoxypentyloxy]-4-biphenylcarbonitrile, C₁₈H₁₇NO₂, crystallizes in space group P2₁ with two independent molecules of identical chirality. The molecules differ significantly only in the conformation of the substituent containing the epoxide ring. With the exception of this ring, the structure approximates closely to the centrosymmetric space group P2₁/n, in which refinement can be achieved with the assumption of twofold disorder of orientation of the epoxide ring and a racemic material. The pseudosymmetry is resolved by a weak subset of h0l reflections (h + l = 2n), which are found to be significant in a synchrotron data set. The two rings of the biphenyl unit are essentially coplanar, in contrast to most 4-cyano-4'-(alkyloxy)biphenyl compounds.

-1