Questions tagged [reaction-mechanism]

The detailed (and as complete as possible) description of plausible or observable pathways leading from reactants to products of a chemical process. This tag should be applied to questions about these processes. It may be applied to hypothetical and/or proposed mechanisms.

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42 views

Acid catalysed dehydration of alcohol with a bicyclo group

Pathway 1: Rate determining step is the formation of carbocation. In this pathway, a conjugated tertiary carbocation is generated as an intermediate. Pathway 2: One of the resonance form of ...
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1answer
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Pyridine synthesis by tin(II) chloride reduction of 5-nitronorbornene

What is the reaction mechanism here? I guess the $\ce{SnCl2}$ reduces $\ce{NO2}$ to $\ce{NH2}$ but then what happens?
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How does ammonium nitrate explode on its own?

I thought ammonium nitrate was an oxidizer that needed to be mixed with fuel to form a high explosive (e.g., ANFO). But apparently there have been accidental explosions involving just the "...
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1answer
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Acid catalysed dehydration of 5-methylidenecyclopent-2-en-1-ol

I think the following reaction is NOT possible. I could not find a mechanism for ring expansion. Is ring expansion possible in any way? Is the following mechanism correct?
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Organic Chemistry sulphonation [closed]

In sulphonation reaction chlorobenzene reacts with concentrated $\ce{H2SO4}$ in presence of heat To give chloro benzene sulfonic acid. Electrophile formed in this process is $\ce{HSO3+}$ which attacks ...
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1answer
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Acids used in Friedel-Crafts alkylation

I am learning adding alkyl groups to benzene using Fridel-Crafts alkylation: I know that it is very common to use $\ce{AlCl3/AlBr3}$ as Lewis acid catalyst in this reaction. But I am just wondering ...
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0answers
110 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 ...
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2answers
54 views

Dehydration of primary alcohol with a cyclobutadiene substituent [closed]

Note: Primary alcohol will follow E2 mechanism, therefore, removal of protonated water and proton (RDS) shall proceed in a single step in the above mechanism. My questions are: 1- According to ...
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Yield of possible products from acid catalysed hydration of an alkene with a phenyl group

Here, (b) is the major product due to formation of tertiary conjugated carbocation. My questions are: 1- Will a kinetically favoured (minor) product (c) form? 2- Is product (d) possible due to high ...
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1answer
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Can I use potassium acetate instead of potassium carbonate?

In the synthesis of N-ethoxycarbonyl L-proline methyl ester from L-proline and ethyl chloroformate, I use $\ce{K2CO3}$ to neutralize $\ce{HCl}$. Can I use $\ce{CH3CO2K}$ instead of $\ce{K2CO3}$? I ...
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What is the mechanism for this intramolecular SN1 reaction?

What is the mechanism for the following intramolecular $\mathrm{S_N1}$ reaction? For this question, my professor hinted at an intramolecular reaction, and he asked us to recall the bromonium ion as ...
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Acid dehydration to ether

Can anyone please help me come up for a curved arrow mechanism for the reaction pictured? I'm familiar with the mechanism for the general acid catalyzed dehydration of butanol, where the arrow comes ...
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Reaction between a carbene and n-pentane

Does the following reaction occur when n-pentane reacts with methylene or does it form some other simpler products due to the reactivity of the carbene? $\ce{CH3-(CH2)3-CH3 + :CH2-> CH3-(CH2)4-CH3}...
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Reaction of primary nitroalkane with nitrous acid

I was reading the reaction of primary nitroalkane with nitrous acid. I read this reaction Another mechanism which I saw: I am now confused whether the first mechanism occur or the second one.I ...
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1answer
360 views

Role of zinc chloride in reaction of ether

I am trying to do a reaction between acetyl chloride $\ce{CH3COCl}$ with diethyl ether. I know that upon using anhydrous $\ce{ZnCl2}$ and heat, I'll get an ester and an alkyl chloride, but I'm not ...
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Why do we get slightly more inversion product than retention product in SN1 reaction?

Theoretically, in $\mathrm{S_N1}$ reaction we should get a racemic mixture as the product because the nucleophile can attack from either side of the formed carbocation. However, many textbooks claim ...
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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. ...
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1answer
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Mechanism of homologation of aldehyde to alkyne: Ohira–Bestmann reaction

This reaction was part of an organic scheme I was doing, and I was wondering what the mechanism of the reaction would be. I tried first forming a carbene by letting $\ce{N2}$ leave from the ...
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1answer
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Why do electron-rich aryl groups have greater migratory aptitudes?

In the following reaction there are three possible aryl groups that can migrate: an unsubstituted phenyl group, a p-methoxyphenyl group, and a p-nitrophenyl group: Why does the electron-rich p-...
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2answers
564 views

Why are two three-membered rings preferred to a single five-membered ring in the reaction of a dihalide with alcoholic KOH?

The given answer is 1,1-dicyclopropylmethanone: Step 1 is abstraction of acidic H by the strong base. Then, there's surely going to be anchimeric assistance. But there can be two places where the ...
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1answer
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Reaction of carboxylic acid with phosphorus trichloride

The reaction of carboxylic acid $\ce{RCOOH}$ with $\ce{PCl5}$/ $\ce{SOCl2}$ / $\ce{PCl3}$ yields an acyl chloride $\ce{RCOCl}$. With $\ce{PCl5}$ and $\ce{SOCl2}$ the reaction is quite simple utilizing ...
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Mechanism of addition of H-X to alkynes

Vinylic carbocation is unstable as the carbocation is bonded to a $\mathrm{sp^2}$ carbon that has high electron density, and pulls the electrons from the carbocation, which is already electron-...
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Reaction of phosphorous pentachloride and sulphur dioxide [closed]

I came across this Reaction of $\ce{PCl5}$ and $\ce{SO2}$ which gives $\ce{POCl3}$ and $\ce{SOCl2}$. And I found this reaction to be interesting because of the fact that two gases are reacting with ...
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1answer
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Regioselectivity in coupling reactions of α-naphthol

I have seen in the following reaction of azo coupling where coupling takes place at position 4 of $\alpha$-naphthol. Now the electron density accumulation is similar at both position $4$ as well as $...
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Synthesis question: Using reductive amination to form pyrrolidine

What molecule results from treating 4-oxopentanal with $\ce{NH4Cl}$ and $\ce{NaCNBH3}$? Why? Is this a good, high yield reaction? I believe that pyrrolidine is formed because amination will convert ...
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2answers
218 views

Formation of toluene from (cyclobutane-1,2,3-triyl)trimethanol using conc. sulphuric acid

In my book this reaction is given without any mechanism: I thought that simple dehydration reaction is going to take place with rearrangement of the carbocation but I have no idea as to how toluene ...
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Mechanism for sodium metal test for hydrogen isocyanide

Sodium metal test is done for detection for acidic hydrogen. In this test, the given compound is treated with Na metal with and tested for the evolution of hydrogen gas. Compounds containing H ...
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0answers
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Alternate pathway of Gabriel synthesis to prepare secondary amine

Can modifying the Gabriel synthesis, which is generally restricted to synthesis of primary amines, be used to synthesise secondary amines? I have attached my idea regarding the synthesis (the final ...
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4answers
310 views

Most favorable position of attack of an electrophile on 4-trifluoromethyl-1,2-diphenylbenzene

Problem This problem is from a FIITJEE AITS paper Which position is most favorable for the attack of an electrophile? Answer My attempt The more favorable position for attack should be the on the ...
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2answers
169 views

Mechansim of reaction between 1‐bromo‐2‐fluorobenzene and furan in the presence of Li/Hg

Problem From FITJEE AITS test series: What is the mechanism of the following reaction? Solution My approach It looks like Birch reduction with $\ce{Li}$ converting to $\ce{Li+}.$ But I can't make ...
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1answer
50 views

How does Gypsum Concrete work?

When mixed with water how does gypsum act as a binder in creating concrete?
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What drives the 'internal return' in SNi?

I just learnt that alcohols can undergo $\mathrm{S_N}i$ with $\ce{SOCl2}$ (without pyridine) to achieve retention: However, what I really do not understand is the 'internal return' step (forming '...
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Acidity of cyclopentadiene [duplicate]

Why is cyclopentadiene more acidic than dibenzocyclopentadiene although in the latter, the negative charge will be more distributed and consumed in resonance stabilization.?
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1answer
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How can I synthesize phenylpiracetam from styrene or benzaldehyde?

I am trying to design a proper synthesis route for phenylpiracetam. I am thinking a good starting material would be styrene or benzaldehyde. Here is my proposed route. Is there a better method? ...
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2answers
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What happens when an alkyne reacts with ammoniacal Cu2Cl2?

My text book provided me with 2 reactions concerning alkynes (Specifically Terminal Alkynes). The first one was the dimerisation of an alkyne on passing it through ammoniacal $\ce{Cu2Cl2}$. All was ...
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Why isn't 4-hydroxybenzoic acid formed along with salicylic acid in Kolbe's reaction?

I've read that in Kolbe's reaction of phenol, i.e. reaction of phenol $(\ce {C6H5OH})$ with $\ce{NaOH}$ forming sodium phenoxide $(\ce {C6H5O^{-}Na^{+}})$, followed by reaction with $\ce{CO_2}$ and ...
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1answer
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Reaction of acyl chlorides with diazomethane and silver(I) oxide

$$\ce{R-COOH ->[SOCl2,CH2N2][Ag2O/CH3OH] X}$$ While solving Carboxylic derivatives recently, I came across this. so following the reagents one by one- $\ce{SOCl2}$ will form acid chloride. $\ce{...
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0answers
35 views

Mechanism of R-OH to R-X using SOCl2 [duplicate]

https://youtu.be/ANlXQdpv6cc?t=1006 In this lecture, I am learning on the reaction of alcohol to alkyl halide using SOCl2 and pyridine. However, there are 2 different approaches on the first step. ...
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Dependance of stability for reaction rate

In our book, it is given: Organic compounds are generally less stable than inorganic compounds. Due to covalent bonding in them, their reaction rates are often slow. First, it is said that they are ...
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1answer
334 views

The product of a reaction series involving 1,3-dithiane, 1-chloro-3-iodopropane and butyllithium

I encountered this question while solving an objective paper. $\ce{BuLi}$ is a strong base and it can be used to abstract a proton from the substrate. Low temperature favours substitution more ...
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1answer
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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? ...
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How to choose between an SN1 and SN2 reaction?

If a compound and a solvent is given, how do we decide whether the reaction proceeds via SN1 or SN2? I am asking this question specifically for a case where the substrate has the leaving group ...
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2answers
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Role of intermediate in determining the exothermic or endothermic nature of reaction

I was given a question to answer: Which of the following reactions is “not” exothermic? $\ce{CH3-Cl + CH3-CH3 -> CH4 + CH3-CH2-Cl}$ $\ce{CH3-Cl + (CH3)3-CH -> CH4 + (CH3)3C-Cl}$ $\ce{CH3-Cl + ...
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Is methylchloride reaction with water SN1 or SN2

I wanted to know if methylchloride reacting with $\ce{H2O}$ would be SN1 or SN2. Methyl halide would not react using SN1 because methyl carbocation is very unstable but it would also not react using ...
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2answers
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Reaction of amines with diethyl oxalate (Hofmann amine separation method)

Why does only one molecule of secondary amine react with diethyl oxalate and two molecules of primary amine react with diethyl oxalate? I feel secondary amine also should have reacted similar to ...
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1answer
109 views

Rate of dehydration for butan-2-ol and butane-2,3-diol

A question taken from a test series (Vibrant, India): Amongst butan-2-ol and butane-2,3-diol, which has higher rate of dehydration? The carbocation formed in butane-2,3-diol is more stable as it ...
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1answer
89 views

Final product of the reaction of alcohol with CH3I in presence of strong base

Identify the final product (B) in the following reaction: I'm not sure how $\ce{NaNH2}$ and $\ce{CH3I}$ will react with the different types of alcohol present here. According to my solution,ether was ...
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0answers
33 views

Solvent shell collapse

In "advanced organic chemistry part A" book page:306&307 , the author uses the term 'solvent shell collapse' when talking about the reason for retention of conformation in tertiary ...
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0answers
43 views

Reactivity comparison between benzaldehyde and acetaldehyde [duplicate]

One of my teacher says that $\ce{Ph-CHO}$ is more reactive than $\ce{CH3-CHO}$ in performing nucleophillic addition reaction because $\ce{—Ph}$ is planar and thus offers less steric hindrance as ...
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What will be the major product when conjugated alkene (like 1,3-butadiene) is reacted with HBr in presence of R2O2?

What will be the major product when conjugated alkene (like 1,3-butadiene) is reacted with $\ce{HBr}$ in the presence of $\ce{R2O2}$? As we know, two products are formed when no $\ce{R2O2}$ is used ...

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