Todd:Chem3x11 ToddL11: Difference between revisions
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=Chem3x11 Lecture 11= | =Chem3x11 Lecture 11= | ||
'''Being constructed | '''Being constructed Mon May 28 - will be ready shortly'''<br> | ||
This lecture is about ''elimination reactions''. | This lecture is about ''elimination reactions''. | ||
| Line 10: | Line 10: | ||
==Key concepts== | ==Key concepts== | ||
* | * The two most common elimination mechanisms, E1 and E2, can often both occur for a given substrate | ||
* The orbital requirements for the reactions tend to give selective, or in some cases specific, stereochemical outcomes | |||
==Eliminations== | ==Eliminations== | ||
An elimination reaction is where a small molecule leaves a carbon-containing molecule via the generation of a double bond. | |||
[[Image:Elimination General.png|thumb|center|500px| '''Scheme 1:''' General Definition of an Elimination]] | |||
We will consider three mechanisms. They differ in the sequence of loss of the two components. | |||
==The E1 Reaction Mechanism== | |||
The X- leaves first, giving a carbocation, which then loses a proton to give the double bond. Rate limiting step is initial loss of anion. Hence rate only depends on concentration of starting material. This mechanism is promoted when the intermediate carbocation is stable. | |||
[[Image:General E1 Mechanism.png|thumb|center|500px| '''Scheme 2:''' The E1 Reaction]] | |||
Revision as of 04:57, 28 May 2012
Chem3x11 Lecture 11
Being constructed Mon May 28 - will be ready shortly
This lecture is about elimination reactions.
(Back to the main teaching page)
Key concepts
- The two most common elimination mechanisms, E1 and E2, can often both occur for a given substrate
- The orbital requirements for the reactions tend to give selective, or in some cases specific, stereochemical outcomes
Eliminations
An elimination reaction is where a small molecule leaves a carbon-containing molecule via the generation of a double bond.
We will consider three mechanisms. They differ in the sequence of loss of the two components.
The E1 Reaction Mechanism
The X- leaves first, giving a carbocation, which then loses a proton to give the double bond. Rate limiting step is initial loss of anion. Hence rate only depends on concentration of starting material. This mechanism is promoted when the intermediate carbocation is stable.
The Licence for This Page
Is CC-BY-3.0 meaning you can use whatever you want, provided you cite me.
