I keep seeing the term cropping up, but cannot seem to find a definition for it. My understanding is that it is an environment in which, when the isomers interact with the environment, the two enantiomers can be distinguished. The only example I can think of is with the human body, where one type of enantiomer can form an enzyme-substrate complex and the other cannot. I can't think of any other examples though. Can you create a chiral environment in a lab?
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My understanding is that it is an environment in which, when the isomers interact with the environment, the two enantiomers can be distinguished.
That's exactly right. Some examples of chiral environments that could be created in a lab would include
- Running a reaction in a chiral solvent
- Running a reaction in a chiral cavity
- Running a reaction with a chiral reagent
- Running a photochemical reaction with a polarized light source
- Carrying out a reaction on a surface to which chiral molecules have been attached (certain clays have this property)
All of these items are like a glove, and each enantiomer will fit differently. This different "fit" leads to transition states of different energy as each enantiomer moves along the reaction coordinate towards the product(s).
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$\begingroup$ Thank you for your answer! I just wanted to clarify: in a chiral environment, is only one of the enantiomers produced, or are both produced but only one of them interacts, or can it be a combination of these two i.e. you have a chiral environment just as long as there is some distinction between the enantiomers, whether it be that only one is created or that both are created but only one interacts with the environment? $\endgroup$– MeepCommented Sep 16, 2014 at 17:04
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1$\begingroup$ If you run a reaction that can produce 2 enantiomers in a chiral environment, then one enantiomer will be preferentially produced. Because in the chiral environment the two possible transition states will be diastereomeric (e.g. of different energy). If the chiral environment is "strong" enough then one enantiomer may be produced to the exclusion of the other enantiomer. I'm not sure I understand the second part of your comment, but both enantiomers and the transition states leading to them are diasteromeric in a chiral environment, $\endgroup$– ronCommented Sep 16, 2014 at 19:37
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$\begingroup$ so the transition states will have different energies leading to the preferred formation of one enantiomer over the other. $\endgroup$– ronCommented Sep 16, 2014 at 19:38