[vivekrai]

Q1.

Attempt:
I could recognize the active Hydrogen in the the reagent. The Nucleophile thus generated will preferably in a conjugate manner will eliminate Cl via SN2. Is the work over here?

Q2.
Compare the three compounds for their Heat of Hydrogenation.

Attempt:
We know that heat of Hydrogenation is inversely proportional to the Stability. Now Stability can be compared on basis of ring strain, Hyperconjugation (You may wish to tell some more) etc. But I need some suggestions.here.

[vivekrai]

Q3.

Attempt:
Unsure what's going on there.

[discodermolide]

reaction 1 will probably produce the epoxide

[vivekrai]

reaction 1 will probably produce the epoxide

Since the medium is aqueous base, wouldn't OH go for a base catalyzed epoxide ring opening? Also the strain developing in the final product doesn't look quite convincing if the energy states are to be compared. There should be some strong favorable point for the ring to be formed. Isn't?

[discodermolide]

reaction 1 will probably produce the epoxide

Since the medium is aqueous base, wouldn't OH go for a base catalyzed epoxide ring opening? Also the strain developing in the final product doesn't look quite convincing if the energy states are to be compared. There should be some strong favorable point for the ring to be formed. Isn't?

No strain here. The anion attacks the aldehyde first, then the O- anion displaces the Cl atom to give the epoxide.
What's your solution then?

[Arctic-Nation]

Epoxides are readily formed from halohydrins. The nucleophilic alkoxide is right next to a very good leaving group, and it will displace that before it realizes the outcome is rather strained. In weak base, the epoxide is stable enough to survive.

For question three, you'll form the N-oxide. Don't think the product will do anything else under the reaction conditions.

[vivekrai]

Epoxides are readily formed from halohydrins. The nucleophilic alkoxide is right next to a very good leaving group, and it will displace that before it realizes the outcome is rather strained. In weak base, the epoxide is stable enough to survive.

I've tried it in this way. It uses your starting material only. Please note that the indicated Carbon atoms have very high acidity and their removal is easy (even though -OH departs) because it extends the conjugation and stability way beyond.
How is it?

[sjb]

Please note that the indicated Carbon atoms have very high acidity and their removal is easy (even though -OH departs) because it extends the conjugation and stability way beyond.
How is it?

The carbons have acidity, and their removal is easy? Are you sure that's what you meant?

[vivekrai]

Please note that the indicated Carbon atoms have very high acidity and their removal is easy (even though -OH departs) because it extends the conjugation and stability way beyond.
How is it?

The carbons have acidity, and their removal is easy? Are you sure that's what you meant?

I meant the H-atoms attached to those carbons.

[Honclbrif]

This whole thing smells like an exercise in Baldwin's Rules.

[orgopete]

I don't agree with the epoxide as the product. Although it could be a transient intermediate, I think it would open being adjacent to the beta diketone. I am skeptical that the furan ring would form under basic conditions. I am accustomed to seeing this reaction under acidic (and dehydrative) conditions though.

[vivekrai]

I don't agree with the epoxide as the product. Although it could be a transient intermediate, I think it would open being adjacent to the beta diketone. I am skeptical that the furan ring would form under basic conditions. I am accustomed to seeing this reaction under acidic (and dehydrative) conditions though.

Okay. Is your product same as what I made? Since the previous arguments of the respected members (to have epoxide product as final) has been shredded.

Also, Sir suggest something for Q2 !

[fledarmus]

For Q2, I think you've started in the right direction. Hydrogenating any of the three structures will all lead to the same product (more stable than any of the three), so the heat of hydrogenation is a measure of the instability of each starting material compared to the product.

So how would you rank the three materials in terms of stability, and why?

[vivekrai]

For Q2, I think you've started in the right direction. Hydrogenating any of the three structures will all lead to the same product (more stable than any of the three), so the heat of hydrogenation is a measure of the instability of each starting material compared to the product.

So how would you rank the three materials in terms of stability, and why?

Firstly we try on the basis of Hyperconjugation. With this, the structure I seems to be the most instable one (least no. of canonical structures). While II and III are not very far from each other. But it seems that the structure II should be more stabilized just like the methyl cyclopropyl cation ? (Here the bonding Pi orbitals are overlapping with the bent orbitals of the ring), So it should be I > III > II ?

[fledarmus]

http://media.wiley.com/product_data/excerpt/01/04708640/0470864001.pdf

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