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I am solving problems based on rates of hydrolysis of compounds but I don't have a general approach to such questions.

Which of the following compounds undergoes hydrolysis faster than the second under comparable conditions? It may be acid catalysed or base catalysed hydrolysis but the conditions must remain the same for each pair.

Compounds

In my view since oxygen is more electronegative than sulfur, hence hydrolysis should be easier for second. But I am not sure about it.

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  • $\begingroup$ Are you intending to hydrolyze the chlorine or the ether/thioether? $\endgroup$
    – electronpusher
    Commented Dec 19, 2016 at 23:53
  • $\begingroup$ @electronpusher thanks for your interest.the question is about hydrolysing chlorine. $\endgroup$
    – Pink
    Commented Dec 19, 2016 at 23:56
  • $\begingroup$ Hydrolysis of the thioether may compete. One might make an argument that the induction of the oxygen might make the alpha carbon more electron-poor than the sulfur compound, but the methylene unit between the O and aloha-C would lessen the inductive effect drastically. Personally I think this comparison might be beyond theory and experiment is necessary. $\endgroup$
    – electronpusher
    Commented Dec 20, 2016 at 1:33

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This is a classic case of neighboring group participation. The hydrolysis of the thioether is significantly faster because the sulfur can displace the chlorine to give a three member ring with a sulfur in it. The ring is quite reactive and will easily be opened by water.

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For reference, you can also look at a compound like mustard gas. It has the same functional groups and is so reactive that is a war gas.

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  • $\begingroup$ Yes that, and of course sulfur is much more nucleophilic than oxygen so NGP is very rapid. $\endgroup$
    – orthocresol
    Commented Dec 20, 2016 at 3:11

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