Michael Reaction

Concept: Concept: General Reaction

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Video Transcript

In this video, we're going to focus on a specific form of conjugate addition to an enone called the Michael reaction. The Michael reaction is a 1,4-conjugate addition. Remember that when I say 1,4-conjugate addition, I'm talking about an enone and I’m talking about adding right there, of an enone with an enolate. Remember that if specifically, if your nucleophile is an enolate, that is called a Michael reaction if that is your nucleophile.
Basically, if you think about it, this is kind of like an aldol times two because your first aldol reaction created the enone. Now, I'm doing a second aldol reaction. I like to think about Michael reaction as an aldol times two. What's cool about these is that they're always going to form the same thing. They’re always going to form 1,5-dicarbonyls. Let me show you how to draw the products first and then I’ll show you the whole mechanism. The products are really easy. In this situation, because we’re doing a conjugate addition, my rules of where to line up your enolate and your electrophile for aldol go out the window. I don't want that anymore. What I prefer you do is to draw the enone at the bottom exactly the way it is but without its double bond and then draw a single bond coming off of the conjugate position, so position 4. Then just draw that attached to your enolate. That's how you draw the product. It's literally enone, enolate, new bond, and then obviously I pointed this out earlier, no pi bond. Don’t draw a double bond there. What I’d like to do is regardless of whatever the nucleophile is, I like to just draw it right on top. But we have to go into the mechanism.
In this next video, I’m going to show you the full mechanism for the Michael reaction. This is also going to help you guys understand why that pi bond isn't there because that can be a little confusing why is that pi bond gone. We're going to talk about it. That's coming up in the next video.

Problem: Determine the product in the following conjugated addition reaction. 

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Problem: Determine the product in the following conjugated addition reaction. 

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Problem: Determine the product in the following conjugated addition reaction

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Michael Reaction Additional Practice Problems

Complete the following reaction supplying the missing product and showing correct regio- and stereochemistry where applicable. If a racemic or diastereomeric mixture forms show all stereoisomers; if no reaction takes place, write N.R.

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Complete the mechanism for the following Michael reaction. Be sure to show arrows to indicate movement of all electrons, write all lone pairs, all formal charges, and all the products for each step. Remember, I said all the products for each step. IF A NEW CHIRAL CENTER IS CREATED IN AN INTERMEDIATE OR THE PRODUCTS, MARK IT WITH AN ASTERISK AND LABEL AS "RACEMIC" IF RELEVANT. IN THE BOX BY EACH SET OF ARROWS, WRITE WHICH OF THE 4 MECHANISTIC ELEMENTS IS INDICATED IN EACH STEP OF YOUR MECHANISM (For example, "Add a proton").

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Predict the products for the following transformations. When necessary indicate the major product and relative stereochemistry.

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Draw the organic product(s) for the following reaction. Indicate stereochemistry where appropriate. Assume an aqueous workup, when necessary. A reasonable answer may be “ No Reaction.”

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α, β, γ, δ unsaturated carbonyl compounds frequently react as shown below. Draw a mechanism for this reaction and give a good reason for why a nucleophile reacts with an alkene at all.  

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Predict the product of the following reaction. 

 

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Provide a detailed mechanism for the following transformation.

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Predict the stepwise mechanism for the reaction shown below: 

 

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Predict the product(s) for the following reaction.

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Which of the following is the direct product of a Michael reaction (1,4 addition of an enolate to a enone)?

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Fill in the roles (abbreviated in parentheses) of the reactants in the boxes. 

Which one is the Michael donor ( D)? Which one is the Michael acceptor ( A)?

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Indicate the order in which the intermediates would appear during the conversion of   1 into 2. The asterisk (*) in the answers indicates the step where the quench is used. 

a) 1 → III – * → II → 2

b) 1 – * →  IV → II → 2

c) 1 → II – * → 2

d) 1→ II → I – * → 2

e) 1 → V → III – * → 2

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Predict the product of the following reaction:

 

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What is the final product of the following reaction?

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Which mechanism best describes the conversion of  A into B?

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