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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20
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1answer
675 views

Regioselectivity of epoxide hydrogenation using Pt versus Ni catalyst

What conditions are applicable for the transformations X and Y, respectively? (a) $\ce{LiAlH4}$, and $\ce{NaBH4}$ (b) $\ce{NaBH4}$, and $\ce{BCl3}$ followed by $\ce{NaBH4}$ (c) $\ce{LiAlH4}$, ...
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1answer
37k 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 ...
14
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2answers
13k 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: $$\ce{C6H12O6 + HI ->[{\Delta}] C6H14}$$ ...
13
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2answers
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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 ...
11
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1answer
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Birch reduction of anisole

Hepworth, Waring and Waring (2002) mentions that: In general, electron-withdrawing substituents make the arene more susceptible to reduction, while the opposite applies for electron-donating ...
10
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1answer
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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 ...
10
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1answer
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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{...
9
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2answers
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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?
8
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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 ...
7
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1answer
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Reduction of carbamate with LAH

The products of the reduction of esters with $\ce {LiAlH4}$ and the products of the reduction of amides with $\ce {LiAlH4}$ are vastly different. The former reduction cleaves the ester and produces ...
7
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1answer
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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 ...
7
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1answer
3k 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 ...
7
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1answer
832 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 ...
7
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130 views

Reduction of hemiaminal by triethylsilane / boron trifluoride

I was trying to understand how the following reaction occurs (taken from a synthesis of homopipecolic acid[1]): I thought that triethylsilane, $\ce{Et3SiH}$, would reduce the ester to an aldehyde. ...
7
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0answers
772 views

Why does reduction using sodium borohydride require a protic solvent?

Recently, I was looking at the chapter on chemoselectivity in Clayden et al.'s Organic Chemistry (2nd ed.). On p. 530, it is mentioned that sodium borohydride reduction only occurs in protic solvents ...
6
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1answer
8k views

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 ...
6
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1answer
254 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 ...
6
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1answer
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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,...
6
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1answer
8k 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 ...
6
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1answer
72 views

Mechanism for simultaneous reduction of nitro group (into aniline) and aromatic substitution (into benzonitrile) by Ethyl cyanoacetate?

I stumbled upon this paper when I'm trying to look at established protocol to synthesize one of the compounds (compound IIk) mentioned in the paper. Studies on Aromatic Nitro Compounds. V. A Simple ...
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3answers
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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 ...
6
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1answer
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How to convert benzamide to benzylamine?

Question Benzamide can be converted to benzylamine using A) $\ce{Br2,\ KOH}$ B) $\ce{PCl5}$ C) $\ce{LiAlH4}$ D) $\ce{NaBH4}$ My answer: Reducing agent is used so C and D ...
5
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3answers
606 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. ...
5
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1answer
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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 ...
5
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1answer
488 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 ...
5
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1answer
7k views

Chemoselectivity in reduction of 3′-nitroacetophenone

When 3′-nitroacetophenone is treated with sodium borohydride, only the carbonyl group is reduced (top); however, when reacted with tin and hydrochloric acid only the nitro group is reduced (bottom). ...
5
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1answer
803 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) ...
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0answers
529 views

Is there an advantage to the Clemmensen or Wolff-Kishner reductions over the Mozingo reaction?

As I understand it (and please correct me if I'm wrong), ketones and aldehydes can be reduced to methylene derivatives via: Clemmensen Reduction (acidic conditions): Wolff-Kishner Reaction (basic ...
4
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2answers
549 views

Selective reduction of nitro group to amine, in benzene ring containing nitrile?

I would like to know if there is a possible route of synthesis that may reduce the shown compound A to the following product B. I would normally reduce a nitro to an amine using $\ce{Pd/C}$ and $\ce{...
4
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1answer
3k views

Best reagent for reducing a ketone in the presence of an alkene

The following reduction is best accomplished with: (a) Zn/Hg, conc. HCl (b) N2H4, C2H5ONa (c) H2, Pd (d) All of the above My thoughts: By looking at the question it is evident that ...
4
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1answer
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Why does the Rosenmund reduction stop at the aldehyde stage?

In the Rosenmund reduction, an acyl chloride can be reduced to an aldehyde by hydrogenation over a palladium catalyst poisoned with barium sulfate. Why isn't the aldehyde product further reduced to ...
4
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1answer
231 views

Reduction of amino acids to corresponding amino alcohols

I've stumbled upon an interesting article about reduction of amino acids and from there to reduction of L-valine to L-valinol using $\ce{LiAlH4}$ in THF. Article says that because of the cost of $\...
4
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2answers
137 views

Chemical Reaction Alternative to O2 Respiration in H2/N2 Atmosphere [closed]

Note: If this question does not belong on this Stack Exchange, please direct me to a more appropriate Stack Exchange. This is a "creative chemistry" question as much or more-so than a "give me the ...
4
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1answer
77 views

Reduction of an Allylic Enoate to afford allylic alcohol in presence of Benzyl Acetal Groups

I have a question that requires finding a reagent for the reduction of an enoate to the corresponding allylic alcohol. Preferably done in one step too with an acid workup at the end too. What types ...
4
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0answers
214 views

How do popular reducing agents react on compounds that have ester, carbonyl, and unsaturated functionalities?

Suppose we have a chemical compound like ethyl 4-oxo-2-cyclopentene-1-carboxylate It is $\ce{-COOC2H5}$ bonded to a five-membered carbon ring with one double bond and the ring has another carbonyl ...
4
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2answers
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Reaction of alkyne with sodium in ethanol

What is the product obtained on the reaction of but-2-yne with $\ce{Na}$ in ethanol? I know that $\ce{Na}$ in liquid $\ce{NH3}$ converts an alkyne to an alkene by anti addition, and $\ce{Na}$ in ...
3
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1answer
142 views

Names of NAD+ and NADH

As part of the biochemical process of glycolysis, NAD+ is reduced to NADH. In other words, nicotinamide adenine dinucleotide is reduced to... nicotinamide adenine dinucleotide? Everywhere I look ...
3
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2answers
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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 ...
3
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1answer
193 views

Specific reduction of certain functional groups

Consider the compound $\ce{Alkyl-(4 oxocyclopent-2-ene)carboxylate (A)}$. For example consider- Now consider the operations: $\ce{1. (A) + (i)BH3/THF (ii) H+}$ $\ce{2. (A) + H2/Pt}$ ...
3
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0answers
114 views

Rationale behind Barton's rules for catalytic hydrogenation

Organic Chemistry by Morrison and Boyd,Seventh Edition says - When cyclohexanones are used as substrates, the stereoselectivity of the reduction is found to be dependent on the acidity or the ...
2
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2answers
286 views

Can protection group be used in a Wolff–Kishner reaction?

How can I modify the ozonolysis of cyclohexene such that one of the aldehyde groups of the product, adipaldehyde, is efficiently protected as a base stable protecting group? I know that attempting to ...
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2answers
3k views

Kinetic isotope effect in nitration of benzene

What is the effect of changing all the hydrogen atoms in benzene to deuterium? For example, which of the following reactions occurs at a faster rate?
2
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2answers
341 views

Out of the given reagents, find the ones to be used to convert benzene to p-aminophenol

$\ce{Br2/FeBr3}$ $\ce{CH3Cl/AlCl3}$ $\ce{KMnO4}$ $\ce{HNO3/H2SO4}$ $\ce{NBS}$/hv $\ce{NaOH}$ $\ce{Sn/HCl}$ $\ce{NH4SH}$ $\ce{NaBH4}$ I'm able to get the amino group onto the ring by using 4 and 7. ...
2
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1answer
783 views

What are the different types of catalysts used in catalytic hydrogenation of alkynes?

This is a question from Org. Chem. by Solomons, Fryhle & Snyder, adapted for JEE by M.S. Chouhan : In the first step, I expected that the reaction would stop at alkene formation via syn ...
2
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1answer
524 views

Could sodium in ethanol reduce amides to amines?

Strong reducing agents like $\ce{LiAlH4}$ can reduce amides to amines. Sodium in ethanol (as a source of protons) is also a very strong reducing agent. Could it be therefore used to, for example, turn ...
2
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1answer
440 views

What side reactions are suppressed by the use of TMSCl in the acyloin condensation?

I was reading about the acyloin condensation and came across a statemant according to which, the use of TMSCl obviates competing reactions. My question is what kind of competing reaction would happen ...
2
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1answer
1k views

Are there any reducing agents for reduction of nitrobenzene to aniline other than Sn/HCl?

I was taught that Sn/HCl should be used for reduction of nitrobenzene to aniline. Can I ask if there are any alternative reducing agents (for example, LiAlH4?) to do the same task?
2
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1answer
211 views

Products for the hydrogenation of the cycloalkene in (3R,4R,5S)-4,5-diamino-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylic acid

Write the products (more than one) for the hydrogenation of the cycloalkene ring in (3⁠R,4⁠R,5⁠S)-4,5-diamino-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylic acid. Reagents are molecular hydrogen with ...
2
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1answer
414 views

Reduction with NH2-NH2 , OH-, and glycol

this question was asked in my exam and I have done it properly until the very third step but unfortunately, although the last step looked like wolfkishner reduction to me I could not do it. My ...
2
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1answer
1k views

Why can't terminal alkynes take part in Birch reduction?

According to my book terminal alkynes are not observed in Birch reduction.Why is this so? The only property I know about them is that they are slightly acidic. Does this have something to do with it? ...