Questions tagged [protecting-groups]

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Wittig reaction without ketone or aldehyde?

In the reaction below the ethylene glycol would react with the ketone in the first step turning it into a protecting group. How would the ylide react, as I thought it only reacts with ketones and ...
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Performing a reaction on one side of piperazine ring

I want to perform a reaction on one nitrogen of piperazine ring while avoiding the reaction on both nitrogens, I am familiar with Boc piperazine however it's expensive and would take 2-3 months to ...
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Planning regio selective protection of functional groups in glycochemisty

Lately I was trying to get a thorough understanding of some questions, I have delved into many research resources such as Scifinder, Google Scholar, and Organic Chemistry Portal. but I'm not satisfied ...
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Friedel–Crafts acylation of substituted anisole

I am attempting to form a synthetic route to a tetrasubstituted benzene compound. In the scheme, there is a step that requires the formation of a carbon–carbon bond in the C-6 position of a methoxy ...
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Why is an allyloxycarbonyl (Alloc) protection group more acid-stable than tert-butyloxycarbonyl (Boc) protecting group?

Why will Boc get cleaved under acidic conditions while Alloc does not? Can Alloc somehow be resonance stabilized? If so, how? Any help would be appreciated.
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Do side chain carboxylic acids need to be protected in peptide synthesis?

Consider the synthesis of the dipeptide Glu–Ala (image). The amino acid Glu (glutamic acid) has two carboxyl groups, where one of them should reacts with the amine group from the other amino acid. ...
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What is the mechanism of benzyl ether hydrogenolysis?

The mechanism for the hydrogenation of alkenes or alkynes using Pd/C is fairly well explained to involve the absorption of hydrogen onto a metal's surface followed by the addition of that hydrogen ...
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Organic chem mechanism [closed]

I don’t understand how the reaction produces this product. In the starting material, there is an $\ce{-OH}$ group attached to carbon 5 but where did the $\ce{-OH}$ group go in the product?
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2 answers
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Reaction of glucose acetal with acetic anhydride

The following problem was asked in JEE Mains 2020 (Sept 2, Shift 1), Consider the following reactions: $\ce{ (i) Glucose + ROH ->[dry HCl] Acetal ->[$x$ eq. of (CH3CO)2O] acetyl derivative }$ $\...
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Synthesis of tripeptide using Merrifield peptide synthesis procedure - Inclusion of asparagine

I am supposed to synthesize tripeptide, $\mathrm{Ala-Asn-Phe}$, using Merrifield peptide synthesis procedure. Accordingly, I have done followings: Attached protected $\mathrm{Phe}$ as the first ...
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Charactaristics of Certain Hydroxyl Protecting Groups

I have been reading through Philip J. Kocienski's book Protecting Groups to try to better understand some of the characteristics of hydroxy protecting groups. I am looking to understand the ...
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Hydroxy Protecting Groups that are not Cleaved Under Acidic Conditions

I am currently designing a synthesis requiring the use of hydroxy protecting groups. The problem I am having is that the protecting group must be able to survive highly acidic conditions. I would have ...
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How are neutral amines effective bases in organic chemistry?

I have found it to be rather strange that neutral amines, such as triethylamine or DIPEA, find applications in organic chemistry in deprotonating alcohols or even α-carbonyl compounds. Amines are ...
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1 answer
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Synthesis for turning synephrenine into N-methylphenethylamine

I am trying to devise a synthesis to change synephrine (4-[1-hydroxy-2-(methylamino)ethyl]phenol) into N-methylphenethylamine. I was figuring that I could remove the hydroxyl group attached to the ...
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t-Boc protection of amide (urea)

I'm trying to prepare protected urea and I'd like to protect it with some alkali stable PG. Is it possible to protect urea with t-Boc? Or is there another way to get boc-protected urea?
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Wittig reaction with an alkyl dibromide

Recently, I have come across a problem, in which a ketone needs to be converted into an alkene. However, in the alkene product, there is also another bromide functional group, at the end of the alkyl ...
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1 answer
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Alcohol protection with ethers

Various ethers are used for hydroxyl protection. My question is about their removal. I know that there are various methods but I want to specify on the use of acids. Certain groups are removed easily ...
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2 votes
2 answers
388 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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What happens to the t-butyl cation in the TFA deprotection of a t-butyl ester?

I am a first-year chemistry graduate student and I am currently learning how to synthesize proteins. I have reached a stage in the process where I need to deprotect a carboxylic acid moiety protected ...
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2 votes
1 answer
190 views

Decomposition of acetonide protecting group in chloroform

Today I purified my compound containing an acetonide protected diol. I took an NMR sample and it looked great, but because I have only little amount of the compound, I put the sample back into the ...
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3 votes
1 answer
796 views

How to form an acetal from an enol ether?

I am having trouble understanding how the protecting group (ethylene glycol) is applied to the alkene next to the ether of highlighted step above. I thought maybe TsOH protonates the alkene as seen in ...
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-1 votes
1 answer
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Trimethylsilyl iodide - Alkyne Reaction

I have synthesized the molecule below possessing a doubly, boc protected heterocyclic amine and a terminal alkyne. Upon attempting a TFA/$\ce{CH2Cl2}$ Boc deprotection I believe my alkyne is being ...
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3 answers
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What are protecting groups in organic chemistry? [closed]

My textbook does not give a very good explanation of what protecting groups are, how they are made, or how they function in Grignard reactions and others. It just gives a couple of examples of ...
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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. ...
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1 vote
1 answer
549 views

Can an ether be selectively hydrolysed in the presence of an ester?

What reaction, or protection/deprotection can be used to transform the ether group of a molecule that also has an ester compound into an alcohol while keeping the ester unchanged? For example: The ...
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3 votes
0 answers
108 views

How can the ketone in a β-ketoester be protected during hydride reduction?

I am supposed to find what X is. I know that $\ce{LiAlH_4}$ will convert all carbonyl groups to alcohols, and the ester group is being reduced. The only way of ending up with a ketone that I can think ...
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16 votes
1 answer
6k views

By what mechanism do acids deprotect primary silyl ethers?

Standard protocols report the selective deprotection of primary silyl ethers in the presence of secondary silyl ethers under acidic conditions, as exemplary shown in scheme 1, a reaction by Hartmann ...
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6 votes
1 answer
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Can a benzyl ether be removed in the presence of an ester?

I'd like to deprotect a benzyl group for a Fráter–Seebach alkylation. Would it be possible to do this with a Birch reduction using Li/NH3 (or Na/NH3), without also reducing the ester carbonyl group? ...
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