InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
A SN2 reaction on chiral substrate is accompanied by inversion of configuration |
|
Answer» Let's say we have chlorofluoromethyl tosylate. As we know that tosylate is a really good leaving group. We chuck in a bunch of iodide and we have an SN2 reaction between the chlorofluoromethyl tosylate and iodide leaving us with chlorofluoroiodomethane and tosylate leaves. We know the stereocentre inverts from the mechanism and I've tried to draw it in a way that shows this. When we assign the stereocentres though, we find they're both R for the reaction as in figure. Note that the oxygen of the tosylate is priority 2 in the starting material, but it's replaced by iodine, which has a priority of 1 when assigning stereochemistry. Examples like this do highlight that there is a bit of arbitrariness to the rules which we use to assign stereochemistry and they can be a little counter-intuitive. |
|