Synthesis and spectroscopic properties of 1,4-diarylbutenynes

Several new diarylbutenynes have been synthesized and analyses of the n.m.r. and u.v. spectra are described. For planar trans-isomers a conformational preference was found for 1-(α-naphthyl)- but not for 1-(β-naphthyl)-4-arylbutenynes. This difference is also found between compounds with C-1 attached to the α- or β-position of a larger aryl group.