Be sure to answer all parts. identify a, b, and c, intermediates in the synthesis of the five-membered ring called an α−methylen
e−γ−butyrolactone. this heterocyclic ring system is present in some antitumor agents. do not draw lone pairs in your answers. 23191 draw structure ... draw structure ... draw structure ... a b c
1 answer:
The complete reaction along with intermediates is given below, with each step highlighted in different color.
Step 1:
In this step an acidic proton at alpha position is abstracted from lactone moiety and corresponding enolate is formed, which is resonance stabilized. Both structures are shown. In this case LDA (<span>Lithium diisopropylamide) acts as a base.
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Step 2:
The enolate formed attacks on Methyl Iodide, as Iodide being greater in size is a good leaving group and alpha methyl moiety is generated.
Step 3:
This step is acid catalyzed Bromination. Bromine is added at alpha position.
Step 4:
This is elimination reaction and is according to <span>Hofmann's Rule. Here less substituted alkene is generated.</span>
Step 1:
In this step an acidic proton at alpha position is abstracted from lactone moiety and corresponding enolate is formed, which is resonance stabilized. Both structures are shown. In this case LDA (<span>Lithium diisopropylamide) acts as a base.
</span>
Step 2:
The enolate formed attacks on Methyl Iodide, as Iodide being greater in size is a good leaving group and alpha methyl moiety is generated.
Step 3:
This step is acid catalyzed Bromination. Bromine is added at alpha position.
Step 4:
This is elimination reaction and is according to <span>Hofmann's Rule. Here less substituted alkene is generated.</span>
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Explanation:
(a) When aqueous solution of hydrochloric and ammonia chemically react together then it results in the formation of ammonium chloride.
The reaction equation for this reaction is as follows.
Now, ioni equation for this reaction is as follows.
Cancelling the spectator ions, the net ionic reaction equation is as follows.
(b) When sodium hydroxide chemically reacts with ammonium chloride then it forms ammonia, water and sodium chloride as follows.
Now, the total ionic equation will be as follows.
Cancelling the spectator ions from the above equation. Then the net ionic equation will be as follows.