Unformatted text preview: C2) 0 hydrogenation is stereoselective, corresponding to addition to less crowded face of
double bond Top face of double bond blocked by this methyl group X '1 CH3 HBC ; H . Hr, Pt H ——‘3—-——>
H c l
H2 adds to bottom face of double bond only this product forms 60 W‘MVWVS W Both products correspond to syn addition of H2 copyrigmo m Mﬂﬂwﬁlli Emerges, w. F’mlsm mulled Ior remained,» or display. Step 1: Hydrogen molecules react with Step 2: The :11ch reacts with the metal
metal atoms at the caialyst surface catalyst, The 1: compouem of the double The relatively strong hydrogen—hydrogen a bond between the two carbons is replaced '
btmd is broken and replaced by two weak by two relatively weak carbonmmetal 6 bonds.
metal—hydrogen bonds, Step 3; A hydrogen atom is transferred Step 4: The second hydrogen atom is transferred,
from the catalyst surface to one of rho forming the alkane, The sites on the catalyst
carbons of the double bond, surface a: which the reaction weaned are
free to accept additional hydrogen and alksne
molecules Problem : What three alkenes yield 2—methylbutane on catalytic hydrogenation? ﬂ
4 C «(L lauds C'EL- 07¢, CR3 /</ ...
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- Summer '08
- Organic chemistry