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Test 1
N/A
6
Organic Chemistry
Undergraduate 2
02/14/2012

Additional Organic Chemistry Flashcards

 


 

Cards

Term

 

 

 

SN1 Reaction

*unimolecular substitution nucleophilic rxn*

Definition
  • has carbocation intermediates
  • results in a partially or completely racemic mixture
  • tertiary carbon is favored
  • nucleophile can attack on either side
  • only [haloalkane] has an affect on the rate of rxn (rate-determining step)
  • rate is governed by relative stabilities of intermediates
  • possible for allyl and benzylic haloalkanes even if primary
  • rarely occur on sp2 carbons and never on sp carbons
  • polar protics are good solvents for SN1
Term

 

 

 

SN2 Reaction
*bimolecular substitution nucleophilic rxn*

Definition
  • no carbocation intermediates
  • complete inversion of configuration
  • backside attack
  • primary carbons
  • both [nucleophile] and [haloalkane] matter for rxn rate
  • rate governed by steric hindrance (caused by bulky groups)
  • never occur on sp2 or sp hybridized carbons
  • polar aprotic solvents are good
Term

 

 

 

Polar Aprotic Solvents

Definition

 

Cannot serve as hydrogen-bond donors. Do not interact strongly with ions and polar molecules. Accelerate SN2 reactions because they don't interact strongly with the nucleophile.

 

ex:
DMSO --> CH3SOCH3

Acetonitrile ---> CH3C=N

DMF --> HCON(CH3)2
Acetone --> CH3COCH3

Term

 

 

Polar Protic Solvents

Definition

 

Hydrogen bond donors (contain -OH groups). Interact strongly with ions and polar molecules. Accelerate SN1 Reactions by stabilizing the charged carbocation intermediate.

 

Ex:
H2O (water)
HCOOH (formic acid)
CH3OH (methanol)
CH3CH2OH (ethanol)
CH3COOH (acetic acid)

 

Term



Best Leaving Groups
Definition

 

 

- best leaving goups are most stable anions...(strongest conjugate acids)
Order of Leaving Groups (Best to Worst)
I-
Br-
Cl- ~ H2O
F-
CH3COO -
HO -
CH3O-
NH2-

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