- #1
nobahar
- 497
- 2
Hello!
I just read that chloride is a better leaving group than an anhydride (when adjacent to a carbonyl, hence the anhydride). (i.e. R-COCl, an Acyl chloride and R-COOCO-R', an anhydride).
I do not understand why this is so. A good leaving group is characterized by being electron withdrawing and a stable anion. Oxygen is more electronegative and a carboxyl group has resonance, which chloride doesn't.
I'd then conclude that the anhydride is a better leaving group; but apparently not!
Any help appreciated.
I just read that chloride is a better leaving group than an anhydride (when adjacent to a carbonyl, hence the anhydride). (i.e. R-COCl, an Acyl chloride and R-COOCO-R', an anhydride).
I do not understand why this is so. A good leaving group is characterized by being electron withdrawing and a stable anion. Oxygen is more electronegative and a carboxyl group has resonance, which chloride doesn't.
I'd then conclude that the anhydride is a better leaving group; but apparently not!
Any help appreciated.