Use of fractional distillation in organic chemistry
The boiling point of an (R)-isomer is the same as the one of the enantiomer, the (S)-isomer.   Since the condensor does not offer a chiral environment to the chiral molecules, there is no discern of them and consequently, neither "single" nor "fractional distillation" separates them.   (You may expose the molecules to a chiral surface to adsorb, though, and separate the enantiomers by chiral gas chromatography; a specialized approach in analytical chemistry and -- because of the scale of amount typically accessible -- much less frequently deployed on a preparative one (a review).)
A successful separation of (cis)-(trans)-isomers by distillation of course depends on how different the boiling points of the pure compounds are.  Looking up the data for (trans)-stilbene (bp 305 C reference) and (cis)-stilbene (307 C at 1 atm reference) suggests other separation techniques may be much more suitable since less demanding.  This especially becomes relevant if you need a technique easy to scale, to manage and to be run continously (e.g., distillation).