Hi all, I am struggling to understand how exactly the reaction takes place between the following:
Ethyl bromide Isopropyl bromide tert-butyl bromide in Sodium Iodide Acetone solution
I have been trying to write the reaction out for each but cannot figure out what happens to the acetone when the substitution occurs and solid precipitate is formed?
Any help would be greatly appreciated, especially with written reactions to supplement… thank you!
My textbook only mentions “acid catalyst” when talking about reactions of 1° alcohols with hydrogen halides. It says that it requires a mixture of concentrated hydrochloric acid and a Lewis acid as a catalyst like zinc chloride to form an alkyl chloride. Any help is greatly appreciated!
To clarify my question, are substituted alkanes (like alkyl halides) saturated?
I understand the mechanism:
- deprotonation of COOH group (due to the base)
- Sn2 reaction (oxygen of COO- attacks the carbon of the alkylhalide, I- leaves)
What i don't really understand is the choice of K2CO3 and DMF. I see this combination A LOT in literature.
K2CO3: I can see that K2CO3 works as a base, but why are these preferred in this kind of reactions? Perhaps because of the solubility of K2CO3 in organic solvents (DMF). After all, carbonates are weak organic bases.
DMF: why use this solvent? It doesnt feel wrong to use for exampleMeOH instead, for example.
https://preview.redd.it/fxo6kh22i2u71.png?width=1420&format=png&auto=webp&s=9ea456fda34c4482c4a1f2e54aecf16466366133
Journal of the American Chemical SocietyDOI: 10.1021/jacs.1c07726
Yu-Feng Zhang, Xiao-Yang Dong, Jiang-Tao Cheng, Ning-Yuan Yang, Li-Lei Wang, Fu-Li Wang, Cheng Luan, Juan Liu, Zhong-Liang Li, Qiang-Shuai Gu, and Xin-Yuan Liu
https://ift.tt/3lg1F3Z
Journal of the American Chemical SocietyDOI: 10.1021/jacs.1c06473
Bingbing Wang, Pan Peng, Wan Ma, Zhao Liu, Cheng Huang, Yangmin Cao, Ping Hu, Xiaotian Qi, and Qingquan Lu
https://ift.tt/2VMnbEo
Was looking at the Darzens for turning an aldehyde into a fun ketone, and I was wondering if it is possible to produce the alkyl alpha halide propionate at a clandestine chemistry level? Sorry if it is named incorrectly, seemed decent enough to get my point across.
List of molecules from Clayden.
Even though the title says SN2 reactions, I want to be able to know why they undergo SN2 instead of SN1 as opposed to memorising them.
The first molecule, MeCl undergoes SN2 because it is not sterically hindered by and substituents.
The secondary alkyl halide prefers to undergo SN2 even though it is slow. This is because secondary carbocations are highly unstable?
Now this is where I am really uncertain. Can the third molecule undergo SN1 in addition to SN2? It can undergo SN2 because there are not that many substituents and its transition state is stabilised by the adjacent pi bond. It can also undergo SN1 because the carbocation will be stabilised by resonance. Yet Clayden's says that the relative reaction rate is lower than the MeCl.
The rationale is the same for the benzyl chloride except that the phenyl ring offers more extensive stabilisation of both the carbocation (if it undergoes SN1) and the transition state (if it undergoes SN2). Maybe the phenyl ring is blocks the approach of the nucleophile and therefore it prefers to undergo SN1?
For the fifth molecule, why does the availability of one lone pair offer so much more stability (for the carbocation) compared to the phenyl ring? The phenyl ring is much bigger than the oxygen. Is the reason because oxygen is more electronegative than the phenyl ring and will therefore lower the energy of the carbocation's orbitals more so than delocalisation across the entire phenyl ring?
Thanks for the help!
A general titanium‐catalyzed boration of alkyl (pseudo)halides with boranes is reported. The system can successfully suppress the undesired hydrodehalogenation process that prevails using other transition‐metal catalysts. The current strategy worked for various alkyl electrophiles, including unactivated alkyl chlorides, with tolerance of reducing functional groups such as ester, alkene, and carbamate. Mechanistic studies reveal a possible radical reaction pathway.
Abstract
An unprecedented and general titanium‐catalyzed boration of alkyl (pseudo)halides (alkyl‐X, X=I, Br, Cl, OMs) with borane (HBpin, HBcat) is reported. The use of titanium catalyst can successfully suppress the undesired hydrodehalogenation products that prevail using other transition‐metal catalysts. A series of synthetically useful alkyl boronate esters are readily obtained from various (primary, secondary, and tertiary) alkyl electrophiles, including unactivated alkyl chlorides, with tolerance of other reducing functional groups such as ester, alkene, and carbamate. Preliminary studies on the mechanism revealed a possible radical reaction pathway. Further extension of our strategy to aryl bromides is also demonstrated.
https://ift.tt/2QECblC
For example Ph-MgBr + CH3CH2-Br -> CH3CH2-Ph. + Mg2+ + Br2
My professor says only sp hybridised grignard reagents may undergo an SN2 reaction but that is unintuitive to me. Are sp3 hybridised grignard reagents weaker nucleophiles than sp hybridised grignard reagents? Thanks for the help!
Nature Chemistry, Published online: 11 January 2021; doi:10.1038/s41557-020-00609-7
A wide variety of bioactive molecules contain stereogenic quaternary carbons, and developing methods for the construction of these stereocentres continues to be an active area of research. Now, it has been shown that a nickel-catalysed enantioconvergent coupling of tertiary alkyl electrophiles with alkenylmetal nucleophiles—which probably proceeds via a radical pathway—can form and set quaternary stereocentres efficiently under mild conditions.
https://ift.tt/3i4YJp5
Journal of the American Chemical SocietyDOI: 10.1021/jacs.1c01486
Stephan M. Rummelt, Paul O. Peterson, Hongyu Zhong, and Paul J. Chirik
https://ift.tt/3wFM03a
I was a little unsure about the overall reaction of alkyl halide and water? Would the products be an alcohol and a hydrogen halide or the alcohol, a hydronium ion, and the halide ion?
Hello everyone.
In a reaction between 1-butanol and thionyl chloride (no bases are present here), I have written what I believe to be the correct mechanism from start to finish. Does this like right to you all? I haven't been able to find a solid explanation online.
I appreciate all the input that I can get!
https://preview.redd.it/8uw0vive15e51.png?width=1225&format=png&auto=webp&s=9bd769e0e0236b150efe139c532d80ffe922031b
A copper‐catalyzed carbonylative borylation of unactivated alkyl halides enables one‐step synthesis of acylborons which can be further transformed into potassium acyltrifluoroborates (KATs) as well as N‐methyliminodiacetyl (MIDA) acylboronate in a one‐pot manner.
Abstract
A copper‐catalyzed carbonylative borylation of unactivated alkyl halides has been developed, enabling efficient synthesis of aliphatic potassium acyltrifluoroborates (KATs) in high yields by treating the in situ formed tetracoordinated acylboron intermediates with aqueous KHF2. A variety of functional groups are tolerated under the mild reaction conditions, and primary, secondary, and tertiary alkyl halides are all applicable. In addition, this method also provides facile access to N‐methyliminodiacetyl (MIDA) acylboronates as well as α‐methylated potassium acyltrifluoroborates in a one‐pot manner. Mechanistic studies indicate a radical atom transfer carbonylation (ATC) mechanism to form acyl halide intermediates that are subsequently borylated by (NHC)CuBpin.
https://ift.tt/3dxMBL8
I understand that hydrocarbons are non polar because the difference in electronegativity between carbon and hydrogen isn't great enough, but that alkyl halides are polar because there is a greater difference in electronegativity between the carbon and the halogen.. however looking at the numbers.. it looks like the difference in electronegativity between carbon and bromine or iodine isn't much at all, and is even less than between carbon and hydrogen, so why would they be polar?
The first electrochemical approach for the nickel‐catalyzed cross‐electrophile coupling was developed. This method provides a novel route to afford 1,1‐diarylalkane derivatives from simple and readily available alkyl and aryl halides in good yields and excellent regioselectivities under mild conditions. The procedure shows good tolerance for a broad variety of functional groups and both primary and secondary alkyl halides can be used. Furthermore, the reaction was successfully scaled up to the multigram scale proving the potential for the industrial application. Mechanistic investigations suggested the formation of a nickel hydride in the electroreductive chain walking arylation which led to the additional development of a new nickel catalyzed hydroarylation of styrenes providing a series of 1,1‐diaryl alkanes in good yields under mild reaction conditions.
https://ift.tt/2ShuvCL
What year were they discovered and by who also is there any reliable source for this information I can’t seem to find it anywhere.
I found this somewhere but seem to have lost the reference. I wanna say an alkyl sulfonate and sodium chloride would be the products. I did a bromination on an aryl alkyl ketone and reduced the excess bromine with bisulfite instead of with sodium carbonate which did not yield the bromoketone.
An unprecedented and general titanium‐catalyzed boration of alkyl (pseudo)halides (alkyl–X, X = I, Br, Cl, OMs) with borane (HBpin, HBcat) is reported. The use of titanium catalyst can successfully suppress the undesired hydrodehalogenation products that prevail using other transition‐metal catalysts. A series of synthetically useful alkyl boronate esters are readily obtained from various (primary, secondary, and tertiary) alkyl electrophiles, including unactivated alkyl chlorides, with tolerance of other reducing functional groups such as ester, alkene, and carbamate. Preliminary studies on the mechanism revealed a possible radical reaction pathway. Further extension of our strategy to aryl bromides is also demonstrated.
https://ift.tt/3s6Q1dy
