I was studying how chirality influences the diastereoselectivity of reactions when I saw 1,4-dihydro-1,4-epoxynaphthalene.


I determine chirality by looking for C with 4 different groups. I see 2 C that accomplish this requirement (sp3 C bond to the O) but both are in a rigid structure, so I can't tell if they're (or not) chiral at all. If they are, can I use the same rules to determine R or S?

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    $\begingroup$ "Is the mirror image superimposable on itself" is sometimes a more useful question to ask, rather than "is there a C with four different groups". $\endgroup$ Feb 7, 2018 at 16:41
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    $\begingroup$ Yes you use the same rules to determine R or S. So what if the thing is rigid? It could have been rigid the other way just as well. $\endgroup$ Feb 7, 2018 at 16:52

1 Answer 1


There are bi-cycles that are chiral, the one shown in the question is not. This can be shown, as pointed out in the comments, by superimposing the molecule on its mirror image, which is possible. Another fast way of ruling out chirality is finding the mirror plane within the molecule (in this case. perpendicular to the both cycles).


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