# Tag Info

Accepted

### Why does alcoholic KOH prefer elimination whereas aqueous KOH prefers substitution?

In alcoholic solution, the $\ce{KOH}$ is basic enough ($\mathrm{p}K_{\mathrm{a}} =15.74$) to deprotonate a small amount of the alcohol molecules ($\mathrm{p}K_{\mathrm{a}}= 16–17$), thus forming ...
• 17.2k

### Use of aqueous KOH and alcoholic KOH in dehydrohalogenation reactions

Aqueous $\ce{KOH}$ is alkaline in nature i.e. it dissociates to produce a hydroxide ion. These hydroxide ions act as a strong nucleophile and replace the halogen atom in an alkyl halide. \ce{RCl + ...
• 909

### How does Hofmann elimination work in this reaction?

Wow, this is an amazing question. The expected reactivity is strongly dependent on the exact structure. For starters, trimethylammonium is about the size of a tert-butyl group. So, expect an A value ...
• 16.7k
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### Rearrangement with sodium iodide (ring opening)

I think the final product will also contain some Bromine atoms attached to it. and the no. of double bonds will be one less than that of the compound given in the picture. I may be wrong but with all ...
• 5,375
Accepted

### Reaction of conjugated alkene with KNH2

Here is a flowchart of what the commenters have stated. An α-elimination occurs stepwise 1 --> 2 --> 3. There is a phenyl migration (bridged?) to afford tolane 4. Look here for this chemistry.
• 13.3k

### Determining if the product would be cis or trans after an anti elimination on fischer projections

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 ...
• 34.6k
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• 192
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### Mechanism of reaction of ketones with isoalkanes under conc. sulfuric acid and heat

This was going to be a comment but it got too long. TL;DR: - This is not an answer, rather a justification for why the question is (probably) wrong. This paper (linked by @Rishi) gives us ...
• 1,418

### What is the major product in the reaction of 2,3-dichlorobutane with sodium amide in liquid ammonia?

These are both reasonable mechanisms, and the question outlines well the factors favoring each. In favor of mechanism I: Low temperature suggests kinetic deprotonation Statistically more terminal ...
• 10.4k

### Reaction of alkyl bromide in presence of piperidine

@User6376297 raised a question: "Could the cyclopropane ring behave like a double bond, making this the analogue of an allyl bromide, and yielding $\ce{R2NCH2CH2CH=CH-tBu}$ by attack on a ...
• 34.6k
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### How were the Hoffman's and the Zaitsev's rule formulated even before the discovery of the electron?

This excerpt is from an article in J Chem Ed (J. Chem. Educ., 1961, 38 (6), p 297 DOI: 10.1021/ed038p297) describing the contents of Markovnikov's 1870 paper in Liebig’s Annalen (translated into ...
Accepted

### Recognising a rate-determining step in E1

Anindya Prithvi has said everything you needed to hear in two sentences. It is true that rate determining step for E1 mechanism is the carbocation formation. Thus, I present here the detail energy ...
• 34.6k
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### Reaction of cyclohexene oxide with LDA

Because of the steric hindrance of the two iPr groups, LDA is a very poor nucleophile. It is, as you note, a very strong base. The two products observed both arise from deprotonation of cyclohexene ...
• 18.2k
Accepted

### Elimination reaction mechanism decision (order = 1 or 2)

$\ce{C-H}$ bond and $\ce{C-D}$ bonds are not the same in energy. $\ce{C-D}$ bond is stronger. So breaking $\ce{C-D}$ bond is more difficult and slower than breaking $\ce{C-H}$ bond. I hope you know ...
• 1,773