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Organic Reaction Mechanisms IV: Elimination
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Saytzeff vs Hofmann products
JEE Main level
Single correct option
Difficulty 2 of 3
o4184
Which pair correctly gives the major alkene from 2-bromo-2-methylbutane?
A
NaOEt
/EtOH: 2-methylbut-1-ene;
(
CH
X
3
)
X
3
COK
/
(
CH
X
3
)
X
3
COH
: 2-methylbut-2-ene
B
Both bases: 2-methylbut-2-ene
C
NaOEt
/EtOH: 2-methylbut-2-ene;
(
CH
X
3
)
X
3
COK
/
(
CH
X
3
)
X
3
COH
: 2-methylbut-1-ene
D
Both bases: 2-methylbut-1-ene
Answer: C
Ethoxide is a small base and gives the more stable trisubstituted Saytzeff alkene, 2-methylbut-2-ene. The bulky tert-butoxide removes the more accessible methyl hydrogen, giving the Hofmann alkene 2-methylbut-1-ene.
Practice Organic Reaction Mechanisms IV: Elimination
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