Which is more highly regioselective: a reaction of an alkene with #BH_3# or with #9-BBN#?
Hydroboration involves the addition of a
It is often followed by oxidation with alkaline hydrogen peroxide to form an alcohol.
The reaction is regioselective, with the
The regioselectivity is enhanced if a bulky dialkylborane,
In equations, it is often written as the blue shorthand symbol.
This sensitivity to steric effects arises because the rigid bicyclic structure prevents internal rotation to relieve steric hindrance in the transition state.