Quick Hydroboration question

[BiomajorPreDent]

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When dealing with alkynes:

i know with excess borane you get a ketone but with 1 eqiv do you get only the enol? I am confused

 

[GiTsticker]

Enols are tautomers of ketones (or aldehydes.)

I think it depends on what you remove the borane with. For example, when the borane complex attacks the alkyne, it can be removed with acetic acid to produce a cis alkene. If you remove the borane with H2O2, then you get anti-mark addition of a vinyl alcohol which tautomerizes to a ketone (aldehyde on terminal alkynes.)