practiceexam3key

practiceexam3key - 1.


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Unformatted text preview: 1.
 Name
the
following
molecules
using
systematic
naming.
 O O a) b) Br C OH c) Br d) C OH Cl bromobenzene benzoic acid 1-bromo-4-chlorobenzene g) 2-methoxypropane OH Cl Br 3-bromobenzoic acid h) i) e) OH f) OH O O 2-methylbutan-1-ol 2-ethylcyclohexanol 4-chloro-3-ethylpentan-2-ol 2-methoxypropane or isopropylmethyl ether l) Br 2-sec-butoxybutane j) O k) O O N H Cl O OH OH ethyl 3-chloro-4-methylpentanoate O m) N-isopropyl-2-methylbutanamide 5-bromo-2-hydroxyhexanoic acid n) O Cl Br O O 4-bromopentanoyl chloride butanoic anhydride 
 2.
 Show
the
expected
products
of
substitution
reactions
for
the
following
reactants.

 Indicate
whether
it
would
undergo
an
SN1
or
SN2
reaction
and
WHY.
 
 
 H 3C H2 C Br + OH H3C H2 C OH + Br Br H3C H2C OH 
 
 
 
 ‐This
reaction
undergoes
SN2
because
the
secondary
carbon
that
needs
to
be
 attacked
by
the
hydroxide
would
not
make
a
stable
carbocation
intermediate
so
the
 halide
needs
to
be
pushed
off
by
the
attack
of
the
nucleophile.

Also,
there
is
little
 crowding
around
the
carbon
to
cause
steric
hindrance
against
the
nucleophile’s
 attack.


 
 
 
 CH3 H 3C C CH3 Br CH3 + H2O H 3C C CH3 OH + H + Br CH3 CH3 H O H Br + H 3C C CH3 + H2O H3C C CH3 
 
 
 ‐This
reaction
undergoes
SN1
because
the
tertiary
carbon
that
needs
to
be
attacked
 by
the
hydroxide
makes
a
stable
carbocation
intermediate,
so
the
halide
can
 spontaneously
dissociate
allowing
for
the
nucleophile
to
attack.

Also,
the
3
methyl
 
 groups
surrounding
the
central
carbon
may
sterically
inhibit
the
nucleophile
from
 attacking
before
the
halide
dissociates.


 
 
 
 
 
 
 3.
 Show
the
expected
products
of
elimination
reactions
for
the
following
reactants.

 You
need
to
decide
if
it
is
an
E1
or
E2
reaction.
 H C H H CH3 C CH3 Br + OH H 2C C CH3 CH3 + Br CH3 H 2C C CH3 Br + H2O 
 
 
 
 
 
 
 
 
 CH3 H 3C C CH3 Br CH3 + H2O H 3C C CH2 + H3O + Br CH3 Br + H 3C C C + H2O H H H 
 
 
 
 
 
 
 
 4.
 Name
the
following
reactant
specifying
the
stereochemistry
as
R
or
S.

Show
the
 product
of
an
SN2
reaction
with
a
hydroxide
ion
and
name
it
with
stereochemistry
 specified.


 H3C CH2 H 3C CH2 
 + H 3C Br H OH H3C H OH (S)-2-bromobutane (R)-butan-2-ol 
 
 5.
 Name
the
following
reactant
specifying
the
stereochemistry
as
R
or
S.

Show
the
 product
of
an
SN1
reaction
with
a
hydroxide
ion
and
name
it
with
stereochemistry
 specified.


 H3C CH2 H3C CH2 H3C CH2 + H3C Br H H2O H3C H OH + H3C OH H (S)-2-bromobutane (R)-butan-2-ol (S)-butan-2-ol 
 6.
 Show
the
major
products
of
the
following
reactions.
 
 
 OH H2CrO4 OH O H2CrO4 OH O H2CrO4 OH NR HI O 2 I O + H2O Δ O H CH3OH HO O CH3O CH3OH O OH 
 
 O O + Cl OH O O O + HCl + Cl 2 NH2 N H + NH3 Cl O O + Cl O H2O OH O + HCl O O + HCl H2O OH + HO O HO O HCl O + + HO O O O + H2N 
 
 
 
 
 O O O O N H + HO 
 O + 2 H2N N H + O HN 3 
 O + O H2O NaOH O Na + HO O H N + O H2O HCl Δ O OH + Cl H3N H N + CH3OH HBr Δ Br O H 3N + O O 
 7.
 Show
the
mechanism
of
base
catalyzed
hydrolysis
of
ethyl
pentanoate
with
sodium
 hydroxide
as
the
base.


 O O 
 NaOH, H2O O O Na + HO O O O + OH + Na OH + Na O O 
 8.
 How
would
you
go
about
adding
a
single
chlorine
substituent
to
benzene?


Show
the
 mechanism.
 OH O Cl + C l2 FeCl3 + HB B H Cl + Cl Cl FeCl3 + FeCl4 9.
 This
is
the
final
step
in
synthesizing
aspirin
(acetylsalicylic
acid).

Given
these
 reactants
and
what
you
know
about
anhy


dride
reactivity
show
the
structure
of
 aspirin.
 O O O OH O O 
 + OH H3PO4 OH O 10.
 Show
the
major
product(s)
of
the
following
reaction,
if
any,
and
give
a
mechanism.
 OH O 
 + H Br Δ Br + H2O Δ O H2 + Br 
 
 
 
 11.
 Show
the
major
product(s)
of
the
following
reaction,
if
any,
and
give
a
mechanism.

 Compare
this
reaction
to
that
of
#10,
and
reason
why
they
are
different.
 
 Amines
do
not
undergo
substitution
reactions
like
alcohols
because
an
anionic
 amine
( NH2 )
is
too
strong
of
a
base
to
be
a
good
leaving
group.

Hydroxide
( OH )
 however,
while
a
strong
base,
can
be
forced
to
leave
with
heat
and
an
acid
present.
 
 
 12.
 Show
the
mechanism
of
the
following
elimination
reaction
and
show
ALL
products.

 Rank
the
products
from
most
to
least
prevalent
in
the
product
mixture.

 
 most-->least prevalent NH2 + HI NR H2SO4 OH + Δ + + HSO4 H3O H O H2 H H H2O or 
 
 
 ...
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This note was uploaded on 07/02/2011 for the course CHEM R340 taught by Professor Tolbert during the Summer '11 term at Indiana.

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