Question

What is an example of hydroboration with `"BH"_3` in alkene ?

Answer 1

I've drawn it out in full here:
http://socratic.org/questions/when-does-hydroboration-oxidation-in-alkyne-occur

...except it's for an alkyne. The difference is that you start with an alkene, you have one less single bond in each step, and you end with an alcohol, not an enol.

`"BH"_3` adds onto the alkene via a syn addition, and ultimately the water adds onto the alkene anti-Markovnikov.