Alkynes w/ hydroboration

[osimsDDS]

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do alkynes form aldehydes via tautomerization when reacted with hydroboration reagents???

Because the OH will add to the least substituted Carbon but then you will get a primary alcohol with a double bond that can form the more stable aldehyde rather then unstable enol form...thanks

 

[shoombol tallah]

terminal alkyne reacted with HBr2, H20/ NaOH(aq) which is hydroboration would form a terminal alcohol bonded to carbon which is double bonded to another carbon. And it would tautomerize into an aldehyde. So to answer your question yes lol

 

[Thundercatz]

I think they form a carboxylic acid. There is a similar question on Achiever. I need too look this up too. I just looked it up and it does form an aldehyde. Scratch my previous response =D.

 

[osimsDDS]

wait give me the achiever question ill look it up, but im pretty sure it undergoes tautomerization to form an aldehyde...but let me know the test # and question, this is a good one it might be the #1 trick on the test haha

 

[Thundercatz]

wait give me the achiever question ill look it up, but im pretty sure it undergoes tautomerization to form an aldehyde...but let me know the test # and question, this is a good one it might be the #1 trick on the test haha

Yea, you are right. It was something else with an alkyne on achiever. Im at my computer in the bedroom now as I am about to sleep, so Ill take a look tomorrow. I think it was on test 1.

I have a feeling you going to rox the DAT man.

 

[osimsDDS]

eh i dunno, i tend to forget easy stuff and nail tough things like destroyer...so anything can happen...thats why im scared $hitless

 

[Thundercatz]

eh i dunno, i tend to forget easy stuff and nail tough things like destroyer...so anything can happen...thats why im scared $hitless

I am the same way bro. I miss the dumbest questions on Achiever and nail the hard ones. I think we just over analyze it. We probably thinking they are out there to trick us.

 

[osimsDDS]

I am the same way bro. I miss the dumbest questions on Achiever and nail the hard ones. I think we just over analyze it. We probably thinking they are out there to trick us.

yea thats true, on the test im gonna take it easy...unless really there ar tricks like halide shifts and tautomerization haha

 

[klutzy1987]

Alkynes form carboxy acids when cleaved not when treated with hydroboration reagents. They just make alcohol and then tautomerize. However i am curious if the aldehude would be unstable and something would happen because aldehydes are very reactive and do not really exist in nature. Perhaps it would undergo an aldol i dunno. I gotta check it up.


P.S. ( note that it is called KETO-enol tautomerism and not called ALDO-enol tautomerism). Hmm??

 

[shoombol tallah]

If any one has the scienceaide reaction table 1 this reaction is in the top middle of the page when you open it up. It has a terminal alkyne reacting with a hydroborating reagent and then tautomerizing into an aldehyde.

 

[osimsDDS]

Alkynes form carboxy acids when cleaved not when treated with hydroboration reagents. They just make alcohol and then tautomerize. However i am curious if the aldehude would be unstable and something would happen because aldehydes are very reactive and do not really exist in nature. Perhaps it would undergo an aldol i dunno. I gotta check it up.


P.S. ( note that it is called KETO-enol tautomerism and not called ALDO-enol tautomerism). Hmm??

yea my bad i thought it was CH3C(triple bond)CH but its CH3C(triple bond)CCH3 which will give you keto-enol tautomerism...

 

[klutzy1987]

yea my bad i thought it was CH3C(triple bond)CH but its CH3C(triple bond)CCH3 which will give you keto-enol tautomerism...

LOL there you go that explains it, although i wonder what would happen with an aldehyde??