Talk:Michael reaction

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It only mentions the Robinson annulation as a subsequent reaction. There is another fault, however, in that Michael Additions are not always between C and C. They can occur in thiols (recall Benzyl mercaptan + Allyl Maleimide).

That is not true. The addition of thiols to Michael acceptors is a conjugate addition, not a Michael addition. Eugene Kwan 11:46, 18 April 2006 (UTC)

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in need of attention, this text describes the robinson annulation (part of aldol condensations) but and is not the actual Michael reaction, Wiki is served with a rewrite.

I might also wonder why it's called the "Michael" reaction? 68.39.174.238 14:21, 12 March 2006 (UTC)

see the article. Eugene Kwan 16:40, 12 March 2006 (UTC)

[edit] Rw

For reference, the mentioned sentences:

1. Michael addition is an important method for alkylation.
2. An α,β-unsaturated carbonyl compound which can undergo a Michael addition is called a Michael acceptor.
3. Michael addition is often easier than the corresponding direct addition to carbonyl, giving selectivity.

I recommend that the changes I made be kept for the following reasons:

• The Michael addition is not commonly thought of as an alkylation of the acceptor, but the nucleophile. If you reacted an enolate with methyl iodide, you wouldn't say that methyl iodide was being alkylated, would you? This may be up for debate. At any rate, the mechanism and details for the Michael addition are completely different than for typical enolate alkylations. Calling it an alkylation may be misleading.
• The significance section is odd. First sentence: see above. Shouldn't we mention that asymmetric methods exist? If we're going to talk about the significance, why not discuss its applications? The second sentence is true, but has nothing to do with the significance. And I don't understan the third sentence at all. What does that mean?
• The next paragraph: this is true, perhaps, but you give no examples, and in any case, it is unclear that the Michael acceptors are causing damage by Michael addition. Unless you can provide some reference, it should be removed. The definition of Robinson annulation is imprecise...I prefer the one I made. One could think of counterexamples which would fit the current definition but wouldn't be Robinson annulations. Eugene Kwan 11:54, 18 April 2006 (UTC)

I'm sorry to be so critical, but I find the recent changes have definitely deviated from what is commonly accepted chemistry terminology and usage. The term "conducts electricity" is unusual, and "becomes an alkoxide which reverts to something else" is much less precise than what was there before. Seeing as I actually do research into the Michael reaction myself, I think I should be acknowledged as the expert here. I'll be happy to make some more concrete changes shortly. Eugene Kwan 04:10, 24 April 2006 (UTC)

• Whether or not we select the term "alkylation", it needs to be shown clearly that Michael reaction is not FGI. It involves an attack at a conjugate acceptor, which receives the alkyl group from the attacking nucleophile. I'm still a student so I can't authoritatively say if this is called alkylation.
• I'm kind of missing the applications too. Especially the asymmetric ones. Sentence 2: You're right that the definition of Michael acceptor has to be moved to the definition(s) section. Sentence 3: I'm going to rewrite this, since it's not kinetic as suggested but thermodynamic selectivity. (E.g. take the simplest enone, and attack it with cyanide. The kinetic product is cyanohydrin, but the reaction is reversible; a slow, irreversible reaction gives the Michael product.)
• DNA base nitrogens attack Michael acceptors. DNA base is alkylated, and useless. I'm adding the reference.
• The mechanism is still a bit hard to read. Pointing out the fact that the conjugated system is essentially a conductor of electricity is just a start. (See also plastics with a metallic shine.) --Vuo 21:49, 25 April 2006 (UTC)