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Radical decarbonylation reactions I. Decarbonylation of 9-phenyl-9-fluorenylacetaldehyde
Tetrahedron Letters No.28, Printed in Great Britain,
RADICAL DECARBONYLATION
DECARBONYLATION
M.
University
of Chemistry of Rhode Island
Kingston, (Received radical
of publications
in the literature, valve
initiated
decarbonylation
to 9-phenylphenanthrene
Rhode Island
1965; in revised
rearrangement in recent
have been the subject
Of the many
uncomplicated +1
form 24 &xy 1965)
reactions
years.
ring expansion.
that the decarbonylation
*1.
14 April
few describe
simultaneous
1.
Vittimberga
Department
number
REACTIONS
OF 9-PHENYL-9-FLUORENYLCETALDEHYDE Bruno
Free
1965, Pergaron Press Ltd.
pp. 2385-2387,
radical
We have
reports
by a rather
that in-
the peroxide
of 9-phenyl-9-fluorenylacetaldehyde was accompanied
that appear
migrations
examined
of a
smooth
(I) and found conversion
(II).
During the latter stages of the preparation of this paper we learned that Brother H. Philip, F.S.C., Lewis College. Lockport. Illinois was also working on these systems. (Eighth Annual Report on Research Sponsored by the Petroleum Research Fund for the period ending August 31, 1963). In a private communication Brother Philip stated that he obtained substantially the same results as we did. Another reaction similar to the one described in this paper is the decarbonylation of (1-methylindanyl)acetaldehyde under free radical conditions and C. A.
to give 1. 1-dimethylindane Schneider, J. Org. Chem.
and 2-methyltetraiin 26. 4196 (1961)].
[J.
W.
Wilt
No.28
2301
I
II
The aldehyde *2, m.p.
179-180’.
fluorene used
was prepared
and Hurwite
aldehyde
(1).
analyses
support
*2.
*3.
114-115”
the assigned
at 2.34
C-H);
and 2.85
, (aqueous
in 64% yield from
and nuclear structure n.m.r.
‘r (13 protons)
ethanol),
DNP
q-chloro-q-phenyl-
by a procedure
for the synthesis
Both infrared
cm. -1 (aldehydic
tiplets
m.p.
and c bloromercuriacetaldehyde
by Curtin
2740
I,
similar
to one
of 8, g. B-triphenylpropion-
magnetic
resonance
(n. m. r.)
of I; IR 1720 cm. - 1 (C-O),
a triplet
at 1.2’r(l
and a doublet
proton),
at 6.62
r
mul-
(2 protons).
+3
All new compounds gave satisfactory microanalyses. The micioanalyses were performed by Micro-Analysis, Inc., Wilmington, Del. The infrared spectra were obtained in potassium bromide on a BairdThe n. m. r. spectra Atomic KM- 1 recording spectrophotometer. were taken on a Varian Associates recording spectrometer (A-60) at 60 MC in deuterated chloroform using tetramethylsilane as the internal standard. One notes that the chemical shifts for all non-aromatic type protons This can in both I and III are displaced from their normal positions. be explained if one considers the magnetic anisotropy of rings A, B, The methylene group of I lies essentially in the plane of the and B’. average position of ring A and therefore would experience a reinforcement of the applied field at this point which would result in a shift of Similarly all protons on carbons its proton resonances to lower field. beyond
the methylene
group, i. e. 0 ,0-CH2CH3 -&H in I and -T-H OCH2CH3 The induced the plane of rings B and B’.
fields in these in ID, lie above rings would shield these protons and cause their resonances to shift to This topic will be discussed further in another publication. higher field.
2385
~0.28
The reaction
was
run at 135-140’
the initiator.
The amount
approximately
49% decarbonylation.
The reaction overnight starting
at room material
104-105’.
as determined and n.m. yield)
*6
r.
from
lII.
+3
indicate
at 2.31
a multiplet The formation
I when ethanol
phenyl-9, *4. +5. +6. *7.
Elemental
1445 m,
1373 ms.
746 ms,
and 2.82
r
Y (6 protons)
(11)*5,
weight
analysis acetal
1139 ms.
of 358
and infrared of I (7.9%
cm.-1
ms;
at 6.32
at 9.2r(3
T pro-
have been spontaneous of lI.
is like that proposed
(2) for the chain decarbonylation
m.p.
1108 ms,
a triplet
the crystallization
of this reaction
on standing
114.5-115.5’,
and a triplet
conceivably
to
was isolated
736 8. and’697
(13 protons),
was added to induce
lo-dihydrophenanthrene
m.p.
III to be the diethyl
of lII could
If the mechanism stein and Seubold
*7
754 ms.
at 6.97
mass
, which had a molecular
spectrometry.
770 w,
crystallized
the crystalline
as
corresponded
9-phenylphenanthrene
75-76’
1500 w,
evolved
yield) +6 , picrate
(45%
m.p.
1601 w,
multiplets
From
recovery)*4,
by mass
1023 ms.
(1 proton), tons).
(55%
monoxide
was a liquid which
temperature.
spectroscopy
; 1.R.
1055 ms, n.m.r.
mixture
(alcohol-water),
and a substance.
of carbon
using di-t-butylperoxide
of aldehydes.
(VI) should have formed
by Winthen 9-
in this reaction
The per cent recovery is based on the total amount of aldehyde (I) used in the reaction. The infrared spectrum of Lz is superimposable on one of 9-phenylphenanthrene supplied to us by Brother I+. -Philip. This yield is based on the amount of aldehyde (I) that reacted or 45 per cent of the total aldehyde used in the reaction. The mass spectrum was determined by Mr. Maurice Baainet. Analytical Laboratory, U. S. Army Natick Laboratories, Natick, Mass.
2336 according
No.28
\*/ 253
to i.he following
scheme.
CH& //”
F
8
1l-l
-
7 =C \‘8’_, 6
\
!i
B,
4
2
3
to-o+* -co
I
-c
A3 I
1
IV
-
t
-
\
etc.
\
.’
leading
to VI.
could result
V
of intermediate
in the reaction in the oxidation
observed.
The failure
considers
the transition
at which
rings
V would also
The failure
products.
It is interesting
p-orbital
_go
None of the dihydro-compound
the reaction
its formation
degree
*
VI
Disproportionation
among
/’
since
to detect
it is likely
to note that phenyl
of this migration states
process
however,
be detected
VI does not preclude
that the presence
of oxygen
(ring A) migration
was not
to occur
of the two possible is determined
that may be attained
of the methylene
could,
a likely
of V to II.
A or B will migrate
of overlap
seem
may be explained migrations. to a great
in the transition
state
group and that of the migrating
if one
The rate extent
by the
between
carbon,
the
2387
No.28 maximum ination
overlap
of molecular
restriction those
and C-8.
This
for ring A migration
tend to relieve
the strain
simultaneously
forming
ring B. through
a bridged
a high energy Work
tions
reveals
work during
stable
intermediate
of ring B would
ring of fluorene V.
is not likely
while
The migration since
in this laboratory
reports
The author
of
this would in-
on several
reac-
are forthcoming.
is greatly
Committee
the summer
the tendency
the migration
radical
with
structure.
is now in progress
Research
considerable
in the activation
would lower
of the 5-membered
the rather
of this type and additional
Rhode Island
in an increase
Furthermore,
at C-9
An exam-
of its ortho-hydrogen6
and consequently
*I3
are coplanar.
that ring A experiences
would result
spirane-type
Acknowledgements:
orbitals
due to the interaction
for this group to migrate.
volve
when these
models
to rotation
on C-l
energy
occurring
indebted
for a fellowship
to the University which
supported
of this
of 1964.
REFERENCES (1) D.
Y.
Curtin
and M.
J. Hurwitz,
J. Amer.
Chem.
Sot.
2,
5381
(1952). (2) S.
Winstein
and F.
H.
Seubold.
J. Amer.
Chem.
Sot.
2,
2916
(1946).
*8.
A similar effect was noted by J. W. Wilt and Brother H. Philip, F.S.C. (J. Org. Chem. 25, 891 (1960)) who observed that the rate of migration of the phenyl group in 1-phenylcyclohexylacetaldehyde was greater than that in l-phenylcyclopentylacetaldehyde.
RADICAL DECARBONYLATION
DECARBONYLATION
M.
University
of Chemistry of Rhode Island
Kingston, (Received radical
of publications
in the literature, valve
initiated
decarbonylation
to 9-phenylphenanthrene
Rhode Island
1965; in revised
rearrangement in recent
have been the subject
Of the many
uncomplicated +1
form 24 &xy 1965)
reactions
years.
ring expansion.
that the decarbonylation
*1.
14 April
few describe
simultaneous
1.
Vittimberga
Department
number
REACTIONS
OF 9-PHENYL-9-FLUORENYLCETALDEHYDE Bruno
Free
1965, Pergaron Press Ltd.
pp. 2385-2387,
radical
We have
reports
by a rather
that in-
the peroxide
of 9-phenyl-9-fluorenylacetaldehyde was accompanied
that appear
migrations
examined
of a
smooth
(I) and found conversion
(II).
During the latter stages of the preparation of this paper we learned that Brother H. Philip, F.S.C., Lewis College. Lockport. Illinois was also working on these systems. (Eighth Annual Report on Research Sponsored by the Petroleum Research Fund for the period ending August 31, 1963). In a private communication Brother Philip stated that he obtained substantially the same results as we did. Another reaction similar to the one described in this paper is the decarbonylation of (1-methylindanyl)acetaldehyde under free radical conditions and C. A.
to give 1. 1-dimethylindane Schneider, J. Org. Chem.
and 2-methyltetraiin 26. 4196 (1961)].
[J.
W.
Wilt
No.28
2301
I
II
The aldehyde *2, m.p.
179-180’.
fluorene used
was prepared
and Hurwite
aldehyde
(1).
analyses
support
*2.
*3.
114-115”
the assigned
at 2.34
C-H);
and 2.85
, (aqueous
in 64% yield from
and nuclear structure n.m.r.
‘r (13 protons)
ethanol),
DNP
q-chloro-q-phenyl-
by a procedure
for the synthesis
Both infrared
cm. -1 (aldehydic
tiplets
m.p.
and c bloromercuriacetaldehyde
by Curtin
2740
I,
similar
to one
of 8, g. B-triphenylpropion-
magnetic
resonance
(n. m. r.)
of I; IR 1720 cm. - 1 (C-O),
a triplet
at 1.2’r(l
and a doublet
proton),
at 6.62
r
mul-
(2 protons).
+3
All new compounds gave satisfactory microanalyses. The micioanalyses were performed by Micro-Analysis, Inc., Wilmington, Del. The infrared spectra were obtained in potassium bromide on a BairdThe n. m. r. spectra Atomic KM- 1 recording spectrophotometer. were taken on a Varian Associates recording spectrometer (A-60) at 60 MC in deuterated chloroform using tetramethylsilane as the internal standard. One notes that the chemical shifts for all non-aromatic type protons This can in both I and III are displaced from their normal positions. be explained if one considers the magnetic anisotropy of rings A, B, The methylene group of I lies essentially in the plane of the and B’. average position of ring A and therefore would experience a reinforcement of the applied field at this point which would result in a shift of Similarly all protons on carbons its proton resonances to lower field. beyond
the methylene
group, i. e. 0 ,0-CH2CH3 -&H in I and -T-H OCH2CH3 The induced the plane of rings B and B’.
fields in these in ID, lie above rings would shield these protons and cause their resonances to shift to This topic will be discussed further in another publication. higher field.
2385
~0.28
The reaction
was
run at 135-140’
the initiator.
The amount
approximately
49% decarbonylation.
The reaction overnight starting
at room material
104-105’.
as determined and n.m. yield)
*6
r.
from
lII.
+3
indicate
at 2.31
a multiplet The formation
I when ethanol
phenyl-9, *4. +5. +6. *7.
Elemental
1445 m,
1373 ms.
746 ms,
and 2.82
r
Y (6 protons)
(11)*5,
weight
analysis acetal
1139 ms.
of 358
and infrared of I (7.9%
cm.-1
ms;
at 6.32
at 9.2r(3
T pro-
have been spontaneous of lI.
is like that proposed
(2) for the chain decarbonylation
m.p.
1108 ms,
a triplet
the crystallization
of this reaction
on standing
114.5-115.5’,
and a triplet
conceivably
to
was isolated
736 8. and’697
(13 protons),
was added to induce
lo-dihydrophenanthrene
m.p.
III to be the diethyl
of lII could
If the mechanism stein and Seubold
*7
754 ms.
at 6.97
mass
, which had a molecular
spectrometry.
770 w,
crystallized
the crystalline
as
corresponded
9-phenylphenanthrene
75-76’
1500 w,
evolved
yield) +6 , picrate
(45%
m.p.
1601 w,
multiplets
From
recovery)*4,
by mass
1023 ms.
(1 proton), tons).
(55%
monoxide
was a liquid which
temperature.
spectroscopy
; 1.R.
1055 ms, n.m.r.
mixture
(alcohol-water),
and a substance.
of carbon
using di-t-butylperoxide
of aldehydes.
(VI) should have formed
by Winthen 9-
in this reaction
The per cent recovery is based on the total amount of aldehyde (I) used in the reaction. The infrared spectrum of Lz is superimposable on one of 9-phenylphenanthrene supplied to us by Brother I+. -Philip. This yield is based on the amount of aldehyde (I) that reacted or 45 per cent of the total aldehyde used in the reaction. The mass spectrum was determined by Mr. Maurice Baainet. Analytical Laboratory, U. S. Army Natick Laboratories, Natick, Mass.
2336 according
No.28
\*/ 253
to i.he following
scheme.
CH& //”
F
8
1l-l
-
7 =C \‘8’_, 6
\
!i
B,
4
2
3
to-o+* -co
I
-c
A3 I
1
IV
-
t
-
\
etc.
\
.’
leading
to VI.
could result
V
of intermediate
in the reaction in the oxidation
observed.
The failure
considers
the transition
at which
rings
V would also
The failure
products.
It is interesting
p-orbital
_go
None of the dihydro-compound
the reaction
its formation
degree
*
VI
Disproportionation
among
/’
since
to detect
it is likely
to note that phenyl
of this migration states
process
however,
be detected
VI does not preclude
that the presence
of oxygen
(ring A) migration
was not
to occur
of the two possible is determined
that may be attained
of the methylene
could,
a likely
of V to II.
A or B will migrate
of overlap
seem
may be explained migrations. to a great
in the transition
state
group and that of the migrating
if one
The rate extent
by the
between
carbon,
the
2387
No.28 maximum ination
overlap
of molecular
restriction those
and C-8.
This
for ring A migration
tend to relieve
the strain
simultaneously
forming
ring B. through
a bridged
a high energy Work
tions
reveals
work during
stable
intermediate
of ring B would
ring of fluorene V.
is not likely
while
The migration since
in this laboratory
reports
The author
of
this would in-
on several
reac-
are forthcoming.
is greatly
Committee
the summer
the tendency
the migration
radical
with
structure.
is now in progress
Research
considerable
in the activation
would lower
of the 5-membered
the rather
of this type and additional
Rhode Island
in an increase
Furthermore,
at C-9
An exam-
of its ortho-hydrogen6
and consequently
*I3
are coplanar.
that ring A experiences
would result
spirane-type
Acknowledgements:
orbitals
due to the interaction
for this group to migrate.
volve
when these
models
to rotation
on C-l
energy
occurring
indebted
for a fellowship
to the University which
supported
of this
of 1964.
REFERENCES (1) D.
Y.
Curtin
and M.
J. Hurwitz,
J. Amer.
Chem.
Sot.
2,
5381
(1952). (2) S.
Winstein
and F.
H.
Seubold.
J. Amer.
Chem.
Sot.
2,
2916
(1946).
*8.
A similar effect was noted by J. W. Wilt and Brother H. Philip, F.S.C. (J. Org. Chem. 25, 891 (1960)) who observed that the rate of migration of the phenyl group in 1-phenylcyclohexylacetaldehyde was greater than that in l-phenylcyclopentylacetaldehyde.