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Questions tagged [organic-reduction]

For questions about reduction reactions in organic chemistry, where a molecule of interest is reduced. Do not use for questions on general redox concepts.

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18 votes
1 answer
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Why does LiAlH4 reduce the double bond of cinnamaldehyde, whereas NaBH4 does not?

I read an answer here about why $\ce{LiAlH_4}$ does not reduce conjugated double bonds, and that $\ce{NaBH_4}$ does. But in the case of cinnamaldehyde, $\ce{LiAlH_4}$ reduces the conjugated double ...
Siddharth Venu's user avatar
22 votes
1 answer
50k views

Why does NaBH4 reduce double bonds conjugated to carbonyl groups, while LiAlH4 does not?

I have been going through reduction of aldehydes using $\ce{LiAlH4}$ and $\ce{NaBH4}$. If there is a double bond conjugated with the carbonyl group, $\ce{LiAlH4}$ doesn't reduce it, leading to an ...
Rajath Radhakrishnan's user avatar
16 votes
1 answer
17k views

Does RedP+HI reduce all carbon functional groups to alkane?

I've seen the related questions 1 and 2, they're not duplicates So. when introducing Red P+HI reduction, our teacher said that it is the strongest reducing agent, and it can reduce any functional ...
Gaurang Tandon's user avatar
20 votes
2 answers
17k views

Reduction of glucose to hexane with hydroiodic acid

My book (NCERT India) states that n-hexane is formed when glucose is heated in the presence of hydrogen iodide. That is, the following reaction takes place: $$\ce{C6H12O6 + HI ->[{\Delta}] C6H14}$$ ...
Apoorv's user avatar
  • 1,523
19 votes
1 answer
11k views

Are groups other than carbonyl reduced by Clemmensen reduction?

According to my textbook, Clemmensen reduction reduces only aldehydes and ketones to alkanes. But in this question: $\ce{Zn-Hg/HCl}$ has reduced both the ketonic and nitro group. Correct answer given ...
Akash Goel's user avatar
15 votes
1 answer
21k views

Why does LiAlH4 reduce an amide to an amine, but only reduce a ketone/aldehyde to an alcohol?

Here are two different reactions in which lithium aluminium hydride, $\ce{LiAlH4}$, reduces a carbonyl group: Why does $\ce{LiAlH4}$ completely remove the oxygen from the amide, but only reduces the ...
mshum's user avatar
  • 305
11 votes
1 answer
16k views

Reaction of phenol and zinc dust

There is a reduction reaction of phenol with zinc dust which is found in many books. $\ce{Ph-OH + Zn -> Benzene + ZnO}$ However, a simple google search fails to explain anything about the ...
S R Maiti's user avatar
  • 5,685
9 votes
2 answers
21k views

Does DIBAL-H reduce carboxylic acids?

Diisobutylaluminium hydride(DIBAL-H) reduces only carboxylic acid, ester or both? The answer given was that it only reduces ester. Is it correct that under any condition carboxylic acids are not ...
sonu's user avatar
  • 279
9 votes
1 answer
479 views

Hydroboration oxidation reaction on trans,trans,trans-1,5,9-cyclododecatriene with carbon monoxide

The given solution: I got this question in an entrance exam coaching test paper in India. Product P is easily covered by the mechanism of simple hydroboration-oxidation reaction, and I've understood ...
Gaurang Tandon's user avatar
8 votes
2 answers
3k views

How can an aromatic ketone be reduced in the presence of a nitro group?

Is it possible to reduce an acyl group to an alkane, but still keep a nitro group intact without its reduction to an amino group? A Clemmensen reduction would reduce the nitro group, and it seems like ...
user avatar
7 votes
1 answer
28k views

Color of precipitate formed on reaction of acetylene with Tollen's Reagent

I am asked to find the color of the precipitate formed by the passage of acetylene gas into an aqueous solution of ammoniacal silver nitrate. I thought ammoniacal silver nitrate was Tollen's reagent,...
user17319's user avatar
  • 179
7 votes
1 answer
2k views

Does a non-terminal alkyne react with sodamide?

Hydrocarbon (A), $\ce{C6H10}$, on treatment with $\ce{H2/Ni}$, $\ce{H2}$/Lindlar catalyst and $\ce{Na}$/liquid $\ce{NH3}$ forms three different reduction products (B),(C) and (D) respectively. (A) ...
Rajdeep Dutta's user avatar
7 votes
1 answer
984 views

Birch Reduction of Benzene

According to my Organic Chemistry Textbook: Benzene can be reduced to 1,4-cyclohexadiene by treating it with an alkali metal (sodium, lithium, or potassium) in a mixture of liquid ammonia and an ...
Serotonin's user avatar
  • 853
3 votes
1 answer
2k views

Acid hydrolysis of Birch-reduced Anisole

The following is a question from Advanced problems in organic chemistry by MS Chouhan: Product $A$ is rather straightforward: and on acidic hydrolysis, the following reaction takes place: Here the ...
Lost Anisole's user avatar
1 vote
1 answer
340 views

Stabilization of ipso and para position in Birch reduction by EWG of aromatic ring

I'm trying to grasp the Birch reduction. In the lecture about it, it's said that the EWG group stabilizes ipso and para position through resonance. I tried to understand that by drawing resonances ...
NK Yu's user avatar
  • 651
17 votes
1 answer
39k views

Reaction mechanism for reduction of nitrobenzene to aniline in catalytic and acidic media

Can anyone explain the reaction mechanism of the two reactions given below? They are the conversion of nitrobenzene to aniline in catalytic ($\ce{H2/Pd}$ in ethanol) and acidic ($\ce{Sn/HCl}$ or $\ce{...
jNerd's user avatar
  • 501
13 votes
2 answers
66k views

Nitrobenzene reduction with (tin) Sn catalyst: Why is C-H bond cleavage preferred over O-H bond cleavage?

I am trying to understand this mechanism for nitrobenzene reduction with $\ce{Sn/HCl}$. I do not understand why it implies that you pull off the $\ce{C-H}$ hydrogen instead of the $\ce{O-H}$ hydrogen ...
Coherent's user avatar
  • 484
13 votes
2 answers
22k views

Reactions of alkynes with sodium/ammonia vs sodium amide

What happens when alkynes react with sodium in ammonia ($\ce{Na/NH3}$), or when they react with sodium amide ($\ce{NaNH2}$)? Are these two sets of conditions different?
geek101's user avatar
  • 1,051
12 votes
1 answer
9k views

How is NaBH4 able to reduce tertiary alkyl halides to alkane but LiAlH4 create an alkene?

When attacking tertiary alkyl halides, aren't both of them just supposed to follow $\mathrm{S_N2}$ and substitute the leaving group with Hydride ion? Apparently only $\ce{NaBH4}$ does it and $\ce{...
PotatoOnTheFloor's user avatar
8 votes
1 answer
2k views

Conversion of benzenediazonium chloride to benzene using lithium aluminium hydride

Why does benzenediazonium chloride get converted to benzene upon reacting with $\ce{H3PO2}$ and not $\ce{LiAlH4}$ ? Also, what is the reaction mechanism of the reaction with $\ce{H3PO2}$ ? This ...
Advil Sell's user avatar
8 votes
1 answer
4k views

Why does Birch reduction of naphthalene with isoamyl alcohol form tetralin instead of 1,4-dihydrodialin (as formed with C2H5OH)?

I recently came across this question, which required me to know the difference between performing a Birch reduction on naphthalene using ethanol and using isopentanol. Why does using isopentanol lead ...
foursix56's user avatar
6 votes
1 answer
10k views

What is the purpose of ammonium chloride in anti hydrogenation of alkynes?

In my organic chemistry textbook, lithium is used to create a free radical of the alkynes, to then allow the anti addition of hydrogen to get an alkene. "The Dissolving Metal Reduction of Alkynes" is ...
yolo123's user avatar
  • 1,845
5 votes
3 answers
1k views

Effect of protecting group on diastereoselectivity of LiAlH4 reduction of α-hydroxyketones

In the reactions above, taken from Tetrahedron Lett. 1982, 23 (23), 2355–2358, the choice of protecting group on the α-hydroxyl group has a large influence on the diastereoselectivity of reduction. ...
user avatar
4 votes
2 answers
5k views

How does di-isobutylaluminium hydride ( DiBAl-H ) reduces carboxylic acid

$\text{DiBAl-H}$ reduces by electrophilic attack and provides hydrogen by $\text{H}^-$ transfer. Unlike $\text{LiAlH}_4$ it does not directly provide $\text{H}^-$ ion. So it should not undergo acid ...
user avatar
1 vote
1 answer
2k views

How does Al-Hg react with carbonyl in presence of concentrated HCl?

In Clemmensen reduction, $\ce{Zn-Hg}$/ $\ce{ conc. HCl}$ reduces the carbonyl $\ce{>C=O}$ to $\ce{>CH2}$, by the following mechanism(?): What happens to the carbonyl group if we replace Zinc ...
Adithya's user avatar
  • 1,411
0 votes
1 answer
88 views

What is the full mechanism for the controlled reduction of an alkyne using LiAlH₄?

Was going through my notes and realised I didn't completely fill them in. The first few steps I think are quite self-explanatory but I'm really confused about the last step where I go from the five-...
ajk's user avatar
  • 49
0 votes
1 answer
510 views

Which one is the stronger base?

I'm studying Wolff-Kishner reduction and I don't understand why after this step the leaving group is $\ce{OH-}$ instead of $\ce{^-HN-NH2}$. I guess it's because hydroxide ion is less strong than the ...
Mirko's user avatar
  • 197
-4 votes
2 answers
1k views

Does H2, Pd/C reduce a conjugated ketone?

Would H2, Pd/C be a sufficient reagent for this reaction to proceed? The question is from a test which asked what would be the most suitable reagent for the above reaction
Patrick Schick's user avatar