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4

$\ce{C-H}$ bond and $\ce{C-D}$ bonds are not the same. $\ce{C-D}$ bond is stronger. So breaking $\ce{C-D}$ bond is more difficult and slower than breaking $\ce{C-H}$ bond. I hope you know the mechanisms of $\mathrm{E1}$ and $\mathrm{E2}$ reactions. In $\mathrm{E1}$ reaction, a carbocation is formed first, which is the rate-determining step (rds). Since rds ...


9

As you have mentioned, the basic Fischer operations are: Vertical positions are below the plane of paper and horizontal positions are Above the plane of paper, thus you have already remember that when working with Fischer projection. What you have to remember about chiral compounds are: If you switch two groups, you get the epimer and if you switch two other ...


9

There are two possible eliminations that can happen (see the image below) As you can see, we then have two final products depending upon which $\ce{H}$ is eliminated. From the image 1a is cis and 2a is trans. Now, how do we decide which one is the major product? This can be based on looking at the stability of the transition state. This means we have to ...


5

Dehalogenation of vicinal dihalides can occur through the E2 mechanism. After some digging, I found this article from 1955. The full text is behind a paywall for me, so I cannot cite the specific rate constants, but the general findings are that trans-1,2-dihalocylohexanes undergo iodide-mediated dehalogenation more rapidly than the cis-stereoisomer. These ...


0

Elimination does occur, but only to form an intermediate. As TRC has mentioned above, this involves a benzyne mechanism. $\ce{NH2+}$ is a very strong base; it is the conjugate base of ammonia, which itself is already a base. Under such strong conditions, the aromaticity of the benzene ring can be broken with the $\ce{NH2+}$ eliminating a hydrogen from the ...


3

Notice, that the first compound (A)can show tautomerism, after drawing the enol form we find that the carbocation lies at the allylic position, which means that it is stabilised through resonance forms, hence the compound A has highest rate of reaction. Hope it helps.


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