In Solomons on page 429 provides a good example. There 3 moles of Propene
react with THF:BH3 to produce one mole of Tripropylborane. The three
hydrogens attached to the Boron go to the double bond of the Propene and
the boron attaches to the other part of the double bond. The hydrogen on
the attaches to the carbon with the fewer hydrogens and thus is
anti-Markovnikov. The Boron had three bonding sites and thus uses three
moles of the alkene. Then H2O2 in basic is added. The boron attachemt
is replaced by an OH and the boron is also oxydized forming BO3-3. The
Mechanism for the boron hydrogen addation to the alkene is on page 428. I
hope that helps.
Rocky Downs
On Sat, 30 Nov 1996 snowdesl@plu.edu wrote:
> Hello all you vacationing chem students-
> I haven't quite mastered the full understanding of hydroboration. get
> that it attaches onto the less substituted carbon atom of the double bond,
> but the final result is a trisubstituted boron atom, and why do we end up
> with 3 mols of alcohol?
> This is probably very basic, but I thought that the boron hydride ion had
> attached hydrogens... Thanks, Stacey
>
>