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Are carbonyl compounds, in general, better electrophiles than alkynes?

For example, would an amine prefer to attack a carbonyl like benzaldehyde (to form an imine) or an alkyne like phenylacetylene (also to form an imine)?

Is there a way to measure their relative electrophilicity's?

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  • $\begingroup$ Why was this downvoted? $\endgroup$
    – Nova
    Commented Sep 27, 2016 at 4:20

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The double bonds in alkenes are usually electron-rich. So firstly they aren't good or even average electrophiles. Thus there are only few cases of nucleophilic addition. So I think definitely, carbonyl compounds are way better than alkynes. Also relative electrophilicity can be easily measured by having a nucleophilic attack on them and analysing the rate of reaction or product ratio which can be easily done with modern chemical methods

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  • $\begingroup$ Right I learned that alkynes are much more susceptible to nucleophilic attack than alkenes, especially in phenylacetylene where the resulting carbanion would be stabilized by resonance with the aromatic ring. $\endgroup$
    – Nova
    Commented Sep 27, 2016 at 4:22
  • $\begingroup$ According to your question,first there's way lot of difference among alkenes andcarbonyls.and the reason to your previous comment is alkynes can show minor electrophilicity character but alkenes don't show. They are purely nucleophilic due to the electron cloud around them and accept on electrophilic attacks $\endgroup$ Commented Sep 27, 2016 at 4:31

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