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Kev Go

Disodium sulfide and ethyl acrylate

Bipolar & Mood Disorders  Follow
Oh I see now, thank you. Except this is Na2S and Ethanol so would that make EtO- Na+ and HS? And then the EtO- deprotonates the HS? Or is the question assuming that I'll know what you've written out? Thanks again

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Aya Memo  Follow
Sodium disulfide in solution forms HS- (if using the nonahydrate form) which is a soft nucleophile. Think about the orbital energy of the sulphur lone pair and why does this make it a soft nucleophile?

Look up Michael addition to see how this reaction works. 

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David Aucoin  Follow
Ah okay thanks, so sulphur's lone pair is easily accessible it's a soft nucleophile. I'm still a bit confused on the mechanism though, I can't really see how it's a Michael addition. Which hydrogen would the base take off in the first step?

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Barry Hall  Follow
Deprotonation occurs at the H-S bond.

Na2S.9H2O dissociates to the following:

Na2S.9H2O ::equil:: NaSH + NaOH + 8H2O

The sodium hydroxide will deprotonate the S-H bond forming the sulfur nucleophile which attacks the ethyl acrylate to form the product shown in your original post. Drawing the mechanism will show how it is a Michael type addition, I use the name for all 1,4 addition reactions and in this context I am probably wrong to use it to describe the process.

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