November 24, 2024, 12:47:06 AM
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Topic: General Organic Chemistry Problems  (Read 8545 times)

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Offline orgopete

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Re: General Organic Chemistry Problems
« Reply #15 on: February 27, 2012, 03:34:07 PM »

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 !

Whether the epoxide could be the product or not, I cannot discern. I could imagine it being the product, but maybe not. I did not think the highlighted carbons would result in anion formation. I thought the beta-diketone hydrogen would be more acidic. I thought a route similar to what I have attached below might occur. Just a guess.

Would the dihydrofuran cyclize in base? Is the CH more acidic than the OH? If you are vigorous enough, it might go. Would the ketone enolize and dimerize also? I don't know. However, this is my conjecture. This reaction requires a stoichiometric amount of base. I could imagine an excess of base being used. Even though the scheme clearly shows the reaction is carried out in base, I surmise the reaction will be acidified before isolation of the product. The authors may have done an acid catalyzed cyclization. Although this cyclization is not a Paal-Knorr Furan synthesis, it is similar. I would have planned to carry out an acid catalyzed cyclization. (If anyone is interested in looking this up just to prove me wrong (again), is this a base catalyzed cyclization?)

For 2, I cannot surpass fledarmus's contribution. I had guessed that II would be most stable as an sp2 carbon would also bring the carbons of a cyclopropane together. For I and III, I just went with more substituted is more stable. So, I had II>III>I
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Offline vivekrai

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Re: General Organic Chemistry Problems
« Reply #16 on: February 28, 2012, 02:47:05 AM »
So, I had II>III>I
I have just written those in order of Heat of Hydrogenation, and yours' is of Stability. Thanks!
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