1. Bredt’s Rule
(Ok)
(Not happening)

2. History and Background
Discovered in 1924 by Julius Bredt while investigating the chemistry of naturally occurring bicyclic terpenes
He’s German
Bredt also was the first to determine the structure of camphor (1893)
Camphor contains a bridged ring

3. What It Says
You can’t have a double bond connected to the bridgehead of a bridged ring system
UNLESS the ring is big enough
Having a double bond as part of the bridgehead would be the equivalent of having a trans double bond on the ring
This would create massive angular strain on the ring

4. What It Says

5. What It’s Good For
Good for predicting the product resulting from elimination reactions of bridged ring systems
Bredt’s
Rule H H B r H
100%
NaOEt
EtOH +
110 oC 0%

6. Exceptions
8-membered rings with double bonds at the bridgehead can be isolated
Less than 7, extremely difficult to find said character

7. Exceptions Anti-Bredt Molecules
7 membered (or less) rings that do have double bonds located at the bridgehead
Example: 2-quinuclidonium tetrafluoroborate

8. Exceptions