Hell-Volhard-Zelinksy Rxn and Mechanism

[@navanieethts28]

Your teaching is good bro.

[@gaeldilamh2572]

my professor gave us this rxn and didn't even care to show us the mechanism..... thank u so much!!

[@gaeldilamh2572]

(he only told us that Zelinsky was a russian scientist who got honored by having a crater on the moon named after him...?)

[@leoastrum4463]

Thank you so much!

[@user-xw1ff6xs9b]

Nice explanation!

[@رؤىكايدأبورمان]

Thank you for your efforts, and thank you for the translation into Arabic.

[@kaustubhnadiger3387]

Isnt the lone pair of alcoholic oxygen in resonance with C=O? So wouldn't it be easier for oxygen of C=O to donate its lone pair instead of lone pair of O in OH?

[@dhyeyparekh4994]

thank you man love from india

[@federica42917]

Thank you so much!💕

[@rafaelzamudio6202]

What happened to the hydrogen from the double bonded oxygen at the end? Nice video!

[@jOeCHEM]

Hey, Rafael! I guess when I made this video, I forgot to explicitly show the cleanup step where something would come along and deprotonate that oxygen. It's just a small acid-base reaction, which is why I guess I forgot to show it when I made the video. Did that make sense (and thanks for watching!)?

[@aimbotofficial1952]

As the oxygen in the H20 is positive it'll take electron from one of the hydrogen and the hydrogen will leave. The end product will be OH

[@naveenlife7721]

Can we used FeBr3 instead of PBr3

[@arsalanmohammaddawoodali2]

On the second last step, where does the hydrogen on the oxygen go? The carbonyl oxygen to be specific

[@jOeCHEM]

Ah, looks like I forgot to show what happened to that H. You can assume something in the reaction will pick that up (like a H2O molecule, for example). In reality, carbonyl oxygens get protonated in solution all the time, but for drawing the product here, you can just use H2O to clean it up and get rid of the positive charge.

[@alya410]

Hi Joe, I dont think the brominated alkyl halide (alpha halo carboxylic acid) need to be catalyzed for the second step. I think water will attack the carbonyl carbon and Br will leave. You have acidic conditions and some Br- in your solution anyhow plus that carbonyl carbon is super electrophilic. Let me know what you think.

[@spurti]

I got phosphorous acid when I repeated rxn mechanism 3 times.

[@BackCorey-d5c]

Daren Green

[@ArmstrongBblythe-f4p]

Smitham Court

[@spurti]

I think the carbonyl oxygen will grab proton from the alpha carbon.

[@lydiahidouche9670]

im not very sur about it but i guess this is wrong :/

[@jOeCHEM]

Hey Lydia! What about the mechanism do you think is incorrect? There are slight variations in how the HVZ reaction can be drawn mechanistically (which can be seen by a quick Google search).

[@lydiahidouche9670]

jOeCHEM oh Hi ! Yeah i was talkikng about the mechanism especially the " H3PO3" thing I search and i didnt find any " valid " reference :/ ( im sorry )

[@jOeCHEM]

@@lydiahidouche9670 Don't be sorry at all! My top priorities are that the explanations are correct and that anyone watching them understands them (so I thank you for watching and for asking a question!). The improvement of the -OH to be a better leaving group attacking PBr3 is definitely accurate. kzbin.info/www/bejne/hGPMloaQiaqIkMU - here is another KZbin video, made by a college professor of chemistry who also shows the creation of H3PO3 Let me know if that makes things more clear, or less clear.

[@lydiahidouche9670]

jOeCHEM oh thank u for taking time to answer me , can I send u on instagram the mechanism we use in my university that is ( for me and ppl that i know ) much easier ?! And accurate Because i think the whole probleme here is why would it react 3 times to release a H3PO3 while it can stop when the HOPBr2 was regenerated ?

[@jOeCHEM]

​@@lydiahidouche9670 So if I was doing this on an exam, I would only show the reaction occur once as well (aka I would stop at HOPBr2). I included the three times to show what actually happens in real life if you performed this reaction. But if that didn't clear things up, absolutely please send me a picture of the mechanism in a DM: instagram.com/joechem_io/