Questions tagged [grignard-reagent]

For questions about Grignard reagents RMgX (R = alkyl/aryl/vinyl, X = halide): their chemical and physical properties and reactions.

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38 views

What is product of reaction of 3-bromo-1,4-cyclohexadiene with Mg in presence of dry ether and heat? [on hold]

At first I thought the reaction is making grignard reagent and only addition of $\ce{Mg}$ will occur with $\ce{Br}$. But the correct answer given by book is benzene.
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109 views

Grignard reagent with sulfur dioxide

I have studied that the Grignard reagent $\ce{RMgX}$ reacts with $\ce{CO2}$ to form $\ce{RCOOH}$ after acid hydrolysis. But does the same apply for sulfur dioxide? Grignard reagents are good bases ...
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Preparation of 3-ethylpentan-3-ol

Is it possible to use CI3TMS (a carbon with three iodo groups and a trimethylsilyl protecting group) and three equivalents of an ethyl grignard reagent to prepare 3-ethylpentan-3-ol? By deprotecting ...
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Reaction rate of Mg with aryl halides

I have been thinking of the rate of reaction of aryl bromide and aryl chloride with $\ce{Mg}$ to form Grignard. When considering the electronegativities the carbon in aryl chloride is more ...
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Grignard alkene on a carbonyl

I was given the following mechanism to prove today post-lecture: and my attempt is given below. Now, when the negative charge on the alkene attacks the carbonyl, the electrons are pushed onto the ...
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Reactivity of Grignard reagent

I had the following question at an exam: What is the fastest reacting compound towards nucleophilic addition with Grignard reagent? (a) Acyl chloride (b) Aldehyde (c) Ester It is ...
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91 views

Reaction of 1 equivalent of Mg in ether with 1,4-dibromobut-2-yne

What will be the product formed the if the reaction of Mg in ether with 1,4-dibromobut-2-yne occurs? At first, I thought the answer would be cyclobutyne, but the correct answer is buta-1,2,3-triene. ...
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76 views

What is wrong in this reaction? [closed]

What is wrong in this reaction? I cannot find anything wrong, please help. Any hints would be appreciated.
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113 views

What will form when Dihalides or Trihalides or Polyhalides react with Magnesium?

I know that "R-X + Mg" gives RMgX. I want to ask if the Halide is Poly, then How's the formation of Grignard take place? For example. If 1,4 - Dibromobutane react with Mg, then what will be the ...
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127 views

Grignard reagent and acidic hydrogen

Why does the Grignard reagent not react as a base in case of ketones even though the α-hydrogen atom in case of ketones is acidic? Grignard reagents do react with ethyne to give hydrocarbons, so why ...
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84 views

Carbonation of Grignard reagent with a carbonyl group present in it

Here's the question in my book (see picture) Option A is a standard reaction which gives a carboxylic acid. Option B is definitely wrong because an acid base reaction will take place and CH4 will be ...
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119 views

Grignard reaction on electron-poor benzyl bromides

I am trying to prepare a Grignard reagent from 4-nitrobenzyl bromide but the reaction just doesn't work. My conditions are: 10 mL of THF (anhydrous); 7.04 mmol of 4-nitrobenzyl bromide; 7.04 mmol of ...
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Is it possible to obtain n-butane by treating halopropane grignard reagent with methanol?

The answer is a,b. My mechanism however doesn't give n-butane when R is propyl. Is this a case of textbook errata? Himanshu Pandey, Advanced Problems In Organic Chemistry, 9th edition ...
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Why might the yield of my synthesis of triphenylmethanol be so poor?

I performed the classic Grignard reagent formation leading into the preparation and purification of triphenylmethanol using phenylmagnesium bromide as my Grignard, and benzophenone as the reagent for ...
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Grignard Reagent in THF vs in Diethyl ether

While learning about the Grignard reagent I was taught this by my teacher, but I couldn’t justify why it was so.. I cannot see how Grignard reagent would react differently in basically an ethereal ...
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Steric Factors on reaction with grignard reagent

I was asked to find the products X and Y. For the product X,Here the grignard reagent and even the carbonyl substrate was too sterically hindered to approach the carbonyl center so no reaction would ...
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299 views

Ring contraction when cyclohexene oxide is treated with methyl Grignard

My book writes that: Recall that epoxides rearrange with Lewis acids in a pinacol-like fashion, and that Grignard reagents in THF exist in the following equilibrium: I approached this ...
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2k views

What is the role of ammonium chloride in the workup of a Grignard reaction?

In the following Grignard reaction, why is aqueous ammonium chloride used to get to the products? I don't see how it participated in or modified the reaction from what is normally expected.
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239 views

How does Grignard reagent form? [duplicate]

So I've read that during the formation of the Grignard reagent, The R-X bond cleaves homolytically forming free radicals. My question is how is this happeneing? Due to the high electronegativity ...
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26 views

Chain elongation with a substituent

Can this compound exist in a stable form. If so, can it be used to add the chloroethyl group to a carbonyl compound
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187 views

Is HMgX also a Grignard Reagent like RMgX?

We do know that the Grignard Reagent is $\ce{RMgX}$ where R is some alkyl group & X is any halogen group. So, my question is that, whether $\ce{HMgX}$ is also a Grignard Reagent like $\ce{RMgBr}$?
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264 views

Can thiols be created using a Grignard reagent?

I'm trying to find information on the synthesis of thiols via Grignard reagents. While looking at the synthesis routes on Wikipedia, it said that a Grignard reagent will react with sulphur to form ...
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509 views

Compatibility of Grignard reagents with aromatic nitro groups [closed]

Is it possible to form a Grignard reagent from 1-chloro-3-nitrobenzene, as shown below? Specifically, will the nitro group react with the Grignard reagent formed?
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331 views

Rearrangement of Grignard reagent formed from exocycloproyl vinyl bromide

First, I prepared the grignard reagent then performed nucleophilic addition to the carbonyl carbon and then did hydrolysis. So basically in my product, $\ce{-Br}$ is replaced by $\ce{-CH2OH}$ But ...
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Which alkyl halides can not form grignard reagent [closed]

Which compounds are not useful for preparation of grignard reagents? a) 4-chlorobut-1-yne b) 2-chloroethan-1-amine c) 1-bromobutan-2-ol d) 4-bromocyclohexan-1-ol
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Reactions of Grignard Reagent: 1,2 vs 1,4 addition

So I was reading through Grignard reagent and I came across this answer by jerepierre, which mentions: In general, Grignard reagents and organolithium reagents add directly to the carbonyl carbon, ...
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777 views

Reaction of Grignard reagent with primary amines

What does the reaction $\ce{CH3CH2NH2 + CH3MgBr ->}$ form? Does it form a secondary amine or a tertiary amine or an alcohol? I can't find what a Grignard reagent does to a primary amine.
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What will be the product of this reaction?

We have an alpha beta unsaturated ether, along with a keto group in the same compound, which is being treated with a grignard reagent shown (assume the grignard reagent is in excess). Will it only ...
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177 views

Reaction of carbonyl cyclic diene with Grignard reagent

Predict the major product of this reaction: The two compounds on the right are the possibilities that I thought of (weren't given in the question). According to me: attack on carbonyl carbon ...
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3k views

Does grignard reagent react with oxygen?

Does this reaction actually take place - $$\ce{C2H5MgCl + O2 ->[H2O] C2H5OH}$$ I never saw this kind of a reaction. I thought that grignard reagent might take a proton from water and just form ...
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309 views

Preparation of an aromatic Grignard reagent

I was tasked with preparing 4-fluorophenylmagnesium chloride from the corresponding aryl chloride. But I've heard that aryl Grignard reagents are very difficult to prepare. I think that the optimal ...
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141 views

The reactions of grignard reagent

Question Find y in this question : The $\ce{ -CH2-Cl}$ below according to me will not take part the reaction (or please correct me) thus my answer is y=2 but actually it's y=3
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Conversion from t-butanol to alkene

How can I accomplish the above conversion? My thoughts: One way of introducing the double bond, would be using the appropriate Grignard Reagent after oxidation of t-butanol (somehow) I think that ...
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Phenol preparation from Grignard reagent

Reaction: Phenyl magnesium bromide in presence of excess oxygen, on acidification yields phenol, as below. My instructor told me that the above reaction occurs, and if the reagent is in excess then ...
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Grignard Reagent and Ester [closed]

Is this answer wrong? I feel like there should be a hydrogen instead of a carbon where I indicated in red. Thank you.
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Mechanism for reaction of an allene with the Grignard Reagent(RMgX)

How does the Grignard Reagent($\ce{RMgX}$) react with an allene $\ce{CH_2=C=CH_2}$ and what are the products formed? This is exactly what I tried to do. Any help will be appreciated.
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Leaving group stability when treated with grignard

Why does $\ce{-NH2}$ not leave in $\ce{RCONH2}$ while in $\ce{RCONR2}$ $\ce{NR2}$ leaves when treated with Grignard? I thought $\ce{NH2}$ should leave as there negative charge is more stable on $\ce{N}...
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Why do orthoesters react with Grignard reagents, but acetals and ketals don't?

My book mentions the synthesis of aldehydes and ketones using alkyl ortho esters. It's called Bodroux-Chichibabin aldehyde synthesis. Now, later, the book mentions this: R- displaces EtO-, giving ...
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270 views

Stereochemistry of product in Grignard-Gilman addition reaction

I would like to know whether the stereochemistry given in the following reaction is correct or not? Which attack is more likely? axial or equatorial? I think I should say pseudo axial or pseudo ...
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270 views

Why is a Grignard reagent not protonated by chloramine?

When $\ce{RMgX}$ (Grignard reagent) reacts with chloramine ($\ce{NH2Cl}$) it forms $\ce{RNH2}$. But why doesn't it form $\ce{RH}$ by taking a hydrogen atom from chloramine as the negative charge so ...
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Reactions of Grignard Reagents with amides

Can Grignard reagents add to amides? It appears from the synthetic pathway shown below that there has been some form of nucleophilic substitution at the carbonyl group. Source: 49th IChO Preparatory ...
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Are there any significant uses of the compound formed by magnesium and anthracene?

In an unusual reaction, magnesium reacts with anthracene in THF to form a grignard-like compound called, prosaically, magnesium anthracene: I remember using it briefly in the 1980s. At the time there ...
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174 views

What are the parameters of protonation of a molecule?

Adding an acid replaces the $\ce{-MgBr+}$ with an $\ce{H+}$. Why does this happen? Is $\ce{H+}$ a better electrophile than $\ce{MgBr+}$? Or, to put it another way, why doesn't $\ce{MgBr}$ stays ...
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Reaction of coumarin with phenylmagnesium bromide

I came across this problem.. I thought that the Grignard reagent, PhMgBr, would cleave the lactone and then subsequently add to the ketone formed, giving an allylic tertiary alcohol after aqueous ...
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Why does magnesium prefer to insert into C–Br bonds over C–Cl bonds?

In the formation of a Grignard reagent from a compound possessing both bromine and chlorine, magnesium preferentially inserts into the C–Br bond over the C–Cl bond. For example, the formation of a ...
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Why do Grignard reagents add to propargyl alcohols?

In Phil Baran's lectures on heterocyclic chemistry at Scripps, one of the lecture problems is concerned with this synthesis of Vioxx: The first step supposedly involves an anti addition of the aryl ...
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Getting 3,4-dimethylhex-3-ene from but-2-ene

How can one get 3,4-dimethylhex-3-ene from but-2-ene ? $\hskip2in$ Using $\ce{Br_2}$ then two equivalents of $\ce{CH_3CH_2MgBr}$, I can get the corresponding alkane (3,4-dimethylhexane) but I don't ...
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Does a Grignard reagent react with enones to give the 1,2- or 1,4- product?

Cyclohexenone, an α,β-unsaturated ketone, is electrophilic at both the carbonyl carbon, as well as the β-carbon. So, it can either undergo 1,2-addition to give the allylic alcohol 1, or 1,4-addition ...
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What are the pros and cons of using Gilman reagent over Grignard reagent to synthesize a hydrocarbon?

As far as I know, in order to synthesize a hydrocarbon $\ce{R-R'}$, Grignard reagent or Gilman reagent could be used. $\ce{RMgX + R'X -> RR' + MgX2}$ $\ce{R2CuLi + R'X -> RR' + LiX + RCu} $ ...