1. Suggest a mechanism for this reaction. Why does conjugate addition occur rather than
direct addition?
O
OSiMe 3
PPh 3
Me3 SiCl
PPh3
Why is the product shown as a cation? If it is indeed a salt, what is the anion?
2. What would be the solvent effects on these reactions? Would they be accelerated or
retarted by a change from nonpolar to a polar solvent?
Br 2
Ph 3P
Ph 3P Br + Br
solvent
O
O
NMe3
heat
+ NMe 3
solvent
O
R
CO2
O
NH 3
OMe
R
solvent
NH 2
3. Define the terms homotopic, enantiotopic, diastereotopic and heterotopic groups in a
molecule?
Are the faces of the carbonyl groups and hydrogens in the following compounds
homotopic, enantiotopic, or diastereotopic?
COOH
Hb
HOOC
Ha
Hb
O
O
O
Ha
COOH
Hb
MeOOC
Ha