-
Sn2 only
- R-X = methyl or 1°
- nucleophile/base = STRONG
-
E2 only
- 3° R-X with STRONG nucleophile/base
- 1°/2° R-X with STRONG, NON-NUCLEOPHILIC (very sterically hindered) base
-
Sn1 && E1
2°/3° R-X with WEAK (neutral) nucleophile/base
-
Sn2 && E2
2° R-X with STRONG nucleophile/base
-
What will this do? Why?
- tBUO-
- - Will not do any SN2, only E2!
- - Really sterically hindered base!
-
Good nucleophiles that are weak bases favor ______ over _______.
substitution, elimination
-
Bulky, nonnucleophilic bases favor _______ over _______.
elimination, substitution
-
To determin the product of a reaction with an alkyl halide: (2 steps)
- 1. classify alkyl halide as 1°, 2° or 3°
- 2. classify base or nucleophile as strong, weak or bulky
-
3° R-X with strong base
- E2 only
- strong base favors Sn2 or E2, but 3° R-X are too sterically hindered to undergo Sn2
-
3° with weak nucleophile/base
- Sn1 and E1
- weak base/nucleophile favors Sn1 and E1
-
1° with strong nucleophile
- Sn2 only
- Strong base/nucleophile favors Sn2 or E2, but 1° R-X are least reactive in elimination ∴ only Sn2
-
1° with strong sterically hindered base
- E2 only
- strong, sterically hindered base cannot act as nucleophile for Sn2
-
2° with strong bases/nucleophile
- Sn2 and E2
- strong base is a strong nucleophile
-
2° with strong, sterically hindered base
- E2 only
- strong, sterically hindered base cannot act as nucleophile
-
2° with weak nucleophile/base
- Sn1 and E1
- weak base or nucleophile favors both
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