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Formation of a 1,2,4-dioxazolidine by electron-transfer photooxygenation of 1-butyl-2,3-diphenylaziridine
Tetrahedron Printed in
Letters,Vo1.24,No.30,pp Great Britain
FORMATION
3047-3050,1983
OF A 1,2,4-DIOXAZOLIDINE
PHOTOOXYGENATION
oo4o-4039/83 $3.00 + 01983 Pergamon Press
.oo Ltd.
BY ELECTRON-TRANSFER
OF l-BUTYL-2,3_DIPHENYLAZIRIDINE
* A. Paul Schaap, Department
Girija
Prasad,
and Steven D. Gagnon
of Chemistry, Wayne State University Detroit, Michigan 48202
Summary: Electron-transfer photooxygenation of l-butyl-2,3_diphenylaziridine with 9,10dicyanoanthracene in oxygen-saturated acetonitrile yields 4-butyl-3,5-diphenyl-1,2,4dioxazolidine. This peroxide is surprisingly stable in nonpolar solvents decomposing to benzaldehyde and N-butylbenzamide upon heating to 100°C in benzene. Treatment with triphenyl phosphine yields benzaldehyde and N-butyl-1-phenylmethanimine.
A variety solvents
in the presence
anthracene quenching
of organic
(DCA).
1
undergo
electron-transfer
of cyano-substituted
aromatic
The key step in this reaction
of the sensitizer
fore, been limited VS.
substrates
to easily
SCE in MeCN.lb
by the substrate. oxidized
We have, however,
involves
recently
described
be rapidly
phenyl-substituted
the corresponding
biphenyl
to yield
as a non-light-absorbing
Our results
cosensitizer
on the photochemical
tigate the DCA-sensitized the electron-transfer 1,2,4-dioxazolidine.
reaction
,-p N
in conjunction
conversion
of epoxides
of an aziridine
Photooxygenation
potentials by which
For example,
ozonides
of other heterocycles.
photooxygenation 435
oxidized.2
with DCA.
a compound
o-o
of
by use of
have led us to investhe first report of of the resulting
2,3_diphenylaziridine
o-o
that
3
We now provide
d/U
there-
photooxygenation
to ozonides
wgu
3047
have,
of less than 2V
can be effected
and the isolation
of -cis-1 -"-butyl-
fluorescence
photooxygenations
a method
in polar
such as 9,10-dicyano-
electron-transfer
with oxidation
does not quench DCA may nevertheless oxiranes
hydrocarbons
DCA-sensitized
substrates
photooxygenation
(L)7 was
3048
carried
out in dry MeCN with 1 x 10
-2
M 1 and 2 x 10
at 10°C under oxygen with a 450-W medium-pressure The reaction biphenyl
was complete
the fluorescence
was not necessary
of DCA in MeCN
(k 9
of the solvent under vacuum the formation hyde
corresponding absorption
tions.
2 was obtained
phenyl-substituted
(6 5.543)
isomer -2b absorbs reaction
by reverse
M-l
s-l
phase HPLC.
is tentatively
at
6 5.879.
No isomerization
1 was not oxidized
3b,9,10
assigned
Pure dioxazolidine
The material
decomposed
must be carried
occurs on silica
gel.
acidic potassium
iodide and ferrous ammonium
the higher The minor
In addition, sodium
condi-
aziridine
lamp in with 102.
as decomposition
by its positive
Treatment
thiocyanate.
of
in 25% yield by preparative
out rapidly
was shown to be a peroxide
field trans-
the reaction
that 1 does not react directly was obtained
to the
is independent
under
during photolysis.
of isomers)
The chromatography
By analogy
configuration.
for 4 h with a 400-W high-pressure
-2 (as a mixture
Removal
(1) along with benzalde-
of stereoisomers.
the cis-phenyl
indicating
quenches
in CDC13 by 300 MHz 'H NMR indicated
-2 are not significantly
Rose Bengal,
of 2
test with
of the mixture
of -2a and
-2b in C6D6 in an NMR tube with Ph3P at 100°C for 15 min gave 2 and imine 4 in quantitative yields.
_2 is remarkably
N-butylbenzamide
stable to thermolysis
(5)afterheating
exhibiting
only 35% decomposition
at 1OO'C for 6 h in C6D6. Cleavage
PhCH=NwBu
+
to -3 and
is more rapid in CDC13.
+
Ph,P=O
4
0 +
PhkNHn-Bu
P
We have reported diphenyloxirane stereochemical epoxides
that cosensitized
gives rise exclusively
involving
photooxygenation
of -cis- and trans-
to -cis-3,5-diphenyl-1,2,4-trioxolane.
result has led us to propose
to ozonides
2
electron-transfer
concerted
a mechanism
addition
of
1
8
of
SCE in MeCN).
the major product -2a with
of starting 1 was detected
MeCN containing
1 efficiently
We have found that the ratio of isomers
upon irradiation
TLC over silica gel.
as a 87:13 mixture
solution.
The addition
= 1.7 v vs.
, E;
of the products
ozonides,
time and that peroxides
oxygenated
lamp using a CuS04-filter
of 83% of 4-_n-butyl-3,5-diphenyl-1,2,4_dioxazolidine
Peroxide
(3).
The solution was irradiated
in this case as aziridine
= 8 . 2 x 10'
and analysis
M DCA.
mercury
in 1.5 h as determined
as a cosensitizer
-4
3b
This striking
for the photochemical
conversion
02 as a 1,3-dipolarophile
to an
of
3049
intermediate
carbonyl
photooxygenation DCA by -1 would isomer.
of aziridine
azomethine
electron
transfer
subsequently oxygen.
11
(Scheme 1).
transfer
azomethine
ylides by dipolarophiles.
by energy
stereochemistry
of
An alternative
transfer
1
excited
to be the most stable
02 to -7a and 7b would
mechanism
literature
on the trapping
from singlet
13
of photo-
involves
back
Ylides -7 could
of ylides 1 in the photooxygenation
and triplet
DCA to
of aziridine
and thermally
-1 is
generated
In some cases the ylides have also been detected
14
the mechanism
of this reaction
of -2a and -2b must remain
photochemical
cycloaddition
respectively.
intermediacy
with the extensive
assignments
1,3-Dipolar
-2a and 3,
consistent
Although
cation with -6a predicted
of singlet
from 02' to -6a and -6b could yield '02 and the corres-
'02 generated
The proposed
in the DCA-sensitized
quenching
from DCA' or 0 ' to 6 to form l and DCA or 302. 2 -
react with
spectroscopically.
may be operative
Electron-transfer
radical
ylides -7a and 7b.
form 1,2,4-dioxazolidines electron
1
form the open aziridine
Exothermic
ponding
A similar mechanism
ylide.
conversion
Acknowledgement.
tentative,
of an aziridine
of this reaction
Support
is not fully established
we have been able to demonstrate
to a 1,2,4-dioxazolidine.
with isomeric
aziridines
from the U.S. Army Research Scheme
hA
DCA
and the stereochemical
A
full
0,
Office
is gratefully
1
‘DCA*
0: +
+
DCA
rr-Bu
rr-Bu Ph Hyk$O
+
Ph 7b
H
‘0,
study of the
is in progress.
+
+
the first
---*
acknowledged.
3050
References
and Notes
(1)
(a) D. H. R. Barton, G. Leclerc, P. D. Magnus, and I. D. Mensies, J. Chem. Sot., Chem. COrnmUll.,447 (1972); (b) J. Eriksen, C. S. Foote, and T. L. Parker, J. Am. Chem. Sot., 99, 6455 (1977); (c) R. K. Haynes, Aust. J. Chem., 21, 121 (1978); (d) K. A. Brown-Wensley, S. L. Mattes, and S. Farid, J. Am. Chem. Sot., &I, 4162 (1978); (e) I. Saito, K. Tamoto, and T. Matsuura, Tetrahedron Lett., 2889 (1979); (f) N. Berenjian, P. deMayo, F. H. Phoenix, and A. C. Weedon, ibid., 4179 (1979); (g) W. Ando, T. Nagashima, K. Saito, and S. Kohmoto, J. Chem. Sot., Chem. Commun., 154 (1979); (h) S. L. Mattes and S. Farid, ibid., 126 (1980); (i) J. Eriksen and C. S. Foote, J. Am. Chem. Sot., 102, 6083 (1980); (j)L. T. Spada and C. S. Foote, ibid., 102, 391 (1980); (k) A. P. Schaap, K. A. Zaklika, B. Kaskar, and L. W.-M. Fung, ibid., 102, 389 (1980); (1) S. L. Mattes and S. Farid, ibid., 104, 1454 (1982); (m) A. P. Schaap, L. Lopez, S. D. Anderson, and S. D. Gagnon, Tetrahedron Lett., 5493 (1982); (n) W. Ando, Y. Kabe, and T. Takata, J. Am. Chem. Sot., 104, 7314 (1982); (0) S. Futamura, S. Kusunose, H. Ohta, and Y. Kaniya, J. Chem. Sot., Chem. Commun., 1223 (1983).
(2)
Presented in part at the IX IUPAC Symposium 1982, Abstr. No. ST 15.
(3)
A. P. Schaap, L. Lopez, and S. D. Gagnon, J. Am. Chem. Sot., 105, 663 (1983); Schaap, S. Siddiqui, S. D. Gagnon, and L. Lopez, ibid., submi=d.
(4)
N-unsubstituted 1,2,4_dioxazolidines can be prepared by the reaction of ketones with HO andNH3: E. G. E. Hawkins, J. Chem. Sot. C, 160 (1971). See also N. Duran, J2 &-g. Chem., 2, 1791 (1974).
(5)
M. V. George has reported that direct UV irradiation of several aziridines in the presence of oxygen gave rise to products that could be rationalized in terms of lO2 addition io azomethine ylides and subsequent decomposition of intermediate 1,2,4_dioxazolidines.
(6)
(a) V. Bhat and M. V. George, Tetrahedron George, J. Org. Chem., 44, 3288 (1979).
(7)
R. N. Loeppky
(8)
The l-cm path-length filter solution was prepared from 27 g of CuSO4.5 H20, 30 g of NaN02, and 50 mL of cont. NH40H diluted with water to 1000 mL.
(9)
on Photochemistry,
Lett.,
and D. H. Smith, J. Org. Chem., s,
4133
(1977);
Pau, France,
July 26,
(b) A. P.
(b) V. Bhat and M. V.
1578 (1976).
1 cis- and trans-3,5-Diphenyl-1,2,4_trioxolanes exhibit H NMR absorptions in CDC13 for the zg protons at 6 6.331 and 6.360, respectively.3b See also: J. H. Hall, R. Huisgen, C. H. Ross, and W. Scheer, J. Chem. Sot., Chem. Commun., 1188 (1971).
(10)
R. Criegee
and H. Korber,
Chem. Ber., 104,
(11)
Evidence
(12)
(a) J. Santamaria, Tetrahedron Lett., 4511 (1981);(b) L. E. Manring, C. Gu, and C. S. Foote, J. Phys. Chem., in press. We thank Professor Foote for a preprint of this paper.
(13)
(a) H. W. Heine and R. E. Peavy, Tetrahedron Lett., 3213 (1966); (b) R. Huisgen, W. Scheer, G. Szeimies, and H. Huber, ibid., 397 (1966); (c) R. Huisgen and H. Mader, Angew. Chem., Int. Ed. Engl., 8, 604 (1969).
(14)
(a). H. W. Heine, R. H. Weese, R. A. Cooper, and A. J. Durbetaki, J. Org. Chem., 2, 2708 (1967); (b) A. Padwa and L. Hamilton, J. Heterocycl. Chem., 4,118 (1967); (c) T. DoMinh and A. M. Troszolo, J. Am. Chem. Sot., 94, 4046 (1972); (d) A. M. Trossolo, T. M. Leslie, A. S. Sarpotdar, R. D. Small, G. J. Ferraudi, T. DoMinh, and R. L. Hartless, Pure Appl. Chem., 51, 261 (1979) and references therein.
for '02 generation
(Received
in
USA
28
1807
in DCA-sensitized
February
1983)
(1971).
photooxygenations
has been reported.
12
Letters,Vo1.24,No.30,pp Great Britain
FORMATION
3047-3050,1983
OF A 1,2,4-DIOXAZOLIDINE
PHOTOOXYGENATION
oo4o-4039/83 $3.00 + 01983 Pergamon Press
.oo Ltd.
BY ELECTRON-TRANSFER
OF l-BUTYL-2,3_DIPHENYLAZIRIDINE
* A. Paul Schaap, Department
Girija
Prasad,
and Steven D. Gagnon
of Chemistry, Wayne State University Detroit, Michigan 48202
Summary: Electron-transfer photooxygenation of l-butyl-2,3_diphenylaziridine with 9,10dicyanoanthracene in oxygen-saturated acetonitrile yields 4-butyl-3,5-diphenyl-1,2,4dioxazolidine. This peroxide is surprisingly stable in nonpolar solvents decomposing to benzaldehyde and N-butylbenzamide upon heating to 100°C in benzene. Treatment with triphenyl phosphine yields benzaldehyde and N-butyl-1-phenylmethanimine.
A variety solvents
in the presence
anthracene quenching
of organic
(DCA).
1
undergo
electron-transfer
of cyano-substituted
aromatic
The key step in this reaction
of the sensitizer
fore, been limited VS.
substrates
to easily
SCE in MeCN.lb
by the substrate. oxidized
We have, however,
involves
recently
described
be rapidly
phenyl-substituted
the corresponding
biphenyl
to yield
as a non-light-absorbing
Our results
cosensitizer
on the photochemical
tigate the DCA-sensitized the electron-transfer 1,2,4-dioxazolidine.
reaction
,-p N
in conjunction
conversion
of epoxides
of an aziridine
Photooxygenation
potentials by which
For example,
ozonides
of other heterocycles.
photooxygenation 435
oxidized.2
with DCA.
a compound
o-o
of
by use of
have led us to investhe first report of of the resulting
2,3_diphenylaziridine
o-o
that
3
We now provide
d/U
there-
photooxygenation
to ozonides
wgu
3047
have,
of less than 2V
can be effected
and the isolation
of -cis-1 -"-butyl-
fluorescence
photooxygenations
a method
in polar
such as 9,10-dicyano-
electron-transfer
with oxidation
does not quench DCA may nevertheless oxiranes
hydrocarbons
DCA-sensitized
substrates
photooxygenation
(L)7 was
3048
carried
out in dry MeCN with 1 x 10
-2
M 1 and 2 x 10
at 10°C under oxygen with a 450-W medium-pressure The reaction biphenyl
was complete
the fluorescence
was not necessary
of DCA in MeCN
(k 9
of the solvent under vacuum the formation hyde
corresponding absorption
tions.
2 was obtained
phenyl-substituted
(6 5.543)
isomer -2b absorbs reaction
by reverse
M-l
s-l
phase HPLC.
is tentatively
at
6 5.879.
No isomerization
1 was not oxidized
3b,9,10
assigned
Pure dioxazolidine
The material
decomposed
must be carried
occurs on silica
gel.
acidic potassium
iodide and ferrous ammonium
the higher The minor
In addition, sodium
condi-
aziridine
lamp in with 102.
as decomposition
by its positive
Treatment
thiocyanate.
of
in 25% yield by preparative
out rapidly
was shown to be a peroxide
field trans-
the reaction
that 1 does not react directly was obtained
to the
is independent
under
during photolysis.
of isomers)
The chromatography
By analogy
configuration.
for 4 h with a 400-W high-pressure
-2 (as a mixture
Removal
(1) along with benzalde-
of stereoisomers.
the cis-phenyl
indicating
quenches
in CDC13 by 300 MHz 'H NMR indicated
-2 are not significantly
Rose Bengal,
of 2
test with
of the mixture
of -2a and
-2b in C6D6 in an NMR tube with Ph3P at 100°C for 15 min gave 2 and imine 4 in quantitative yields.
_2 is remarkably
N-butylbenzamide
stable to thermolysis
(5)afterheating
exhibiting
only 35% decomposition
at 1OO'C for 6 h in C6D6. Cleavage
PhCH=NwBu
+
to -3 and
is more rapid in CDC13.
+
Ph,P=O
4
0 +
PhkNHn-Bu
P
We have reported diphenyloxirane stereochemical epoxides
that cosensitized
gives rise exclusively
involving
photooxygenation
of -cis- and trans-
to -cis-3,5-diphenyl-1,2,4-trioxolane.
result has led us to propose
to ozonides
2
electron-transfer
concerted
a mechanism
addition
of
1
8
of
SCE in MeCN).
the major product -2a with
of starting 1 was detected
MeCN containing
1 efficiently
We have found that the ratio of isomers
upon irradiation
TLC over silica gel.
as a 87:13 mixture
solution.
The addition
= 1.7 v vs.
, E;
of the products
ozonides,
time and that peroxides
oxygenated
lamp using a CuS04-filter
of 83% of 4-_n-butyl-3,5-diphenyl-1,2,4_dioxazolidine
Peroxide
(3).
The solution was irradiated
in this case as aziridine
= 8 . 2 x 10'
and analysis
M DCA.
mercury
in 1.5 h as determined
as a cosensitizer
-4
3b
This striking
for the photochemical
conversion
02 as a 1,3-dipolarophile
to an
of
3049
intermediate
carbonyl
photooxygenation DCA by -1 would isomer.
of aziridine
azomethine
electron
transfer
subsequently oxygen.
11
(Scheme 1).
transfer
azomethine
ylides by dipolarophiles.
by energy
stereochemistry
of
An alternative
transfer
1
excited
to be the most stable
02 to -7a and 7b would
mechanism
literature
on the trapping
from singlet
13
of photo-
involves
back
Ylides -7 could
of ylides 1 in the photooxygenation
and triplet
DCA to
of aziridine
and thermally
-1 is
generated
In some cases the ylides have also been detected
14
the mechanism
of this reaction
of -2a and -2b must remain
photochemical
cycloaddition
respectively.
intermediacy
with the extensive
assignments
1,3-Dipolar
-2a and 3,
consistent
Although
cation with -6a predicted
of singlet
from 02' to -6a and -6b could yield '02 and the corres-
'02 generated
The proposed
in the DCA-sensitized
quenching
from DCA' or 0 ' to 6 to form l and DCA or 302. 2 -
react with
spectroscopically.
may be operative
Electron-transfer
radical
ylides -7a and 7b.
form 1,2,4-dioxazolidines electron
1
form the open aziridine
Exothermic
ponding
A similar mechanism
ylide.
conversion
Acknowledgement.
tentative,
of an aziridine
of this reaction
Support
is not fully established
we have been able to demonstrate
to a 1,2,4-dioxazolidine.
with isomeric
aziridines
from the U.S. Army Research Scheme
hA
DCA
and the stereochemical
A
full
0,
Office
is gratefully
1
‘DCA*
0: +
+
DCA
rr-Bu
rr-Bu Ph Hyk$O
+
Ph 7b
H
‘0,
study of the
is in progress.
+
+
the first
---*
acknowledged.
3050
References
and Notes
(1)
(a) D. H. R. Barton, G. Leclerc, P. D. Magnus, and I. D. Mensies, J. Chem. Sot., Chem. COrnmUll.,447 (1972); (b) J. Eriksen, C. S. Foote, and T. L. Parker, J. Am. Chem. Sot., 99, 6455 (1977); (c) R. K. Haynes, Aust. J. Chem., 21, 121 (1978); (d) K. A. Brown-Wensley, S. L. Mattes, and S. Farid, J. Am. Chem. Sot., &I, 4162 (1978); (e) I. Saito, K. Tamoto, and T. Matsuura, Tetrahedron Lett., 2889 (1979); (f) N. Berenjian, P. deMayo, F. H. Phoenix, and A. C. Weedon, ibid., 4179 (1979); (g) W. Ando, T. Nagashima, K. Saito, and S. Kohmoto, J. Chem. Sot., Chem. Commun., 154 (1979); (h) S. L. Mattes and S. Farid, ibid., 126 (1980); (i) J. Eriksen and C. S. Foote, J. Am. Chem. Sot., 102, 6083 (1980); (j)L. T. Spada and C. S. Foote, ibid., 102, 391 (1980); (k) A. P. Schaap, K. A. Zaklika, B. Kaskar, and L. W.-M. Fung, ibid., 102, 389 (1980); (1) S. L. Mattes and S. Farid, ibid., 104, 1454 (1982); (m) A. P. Schaap, L. Lopez, S. D. Anderson, and S. D. Gagnon, Tetrahedron Lett., 5493 (1982); (n) W. Ando, Y. Kabe, and T. Takata, J. Am. Chem. Sot., 104, 7314 (1982); (0) S. Futamura, S. Kusunose, H. Ohta, and Y. Kaniya, J. Chem. Sot., Chem. Commun., 1223 (1983).
(2)
Presented in part at the IX IUPAC Symposium 1982, Abstr. No. ST 15.
(3)
A. P. Schaap, L. Lopez, and S. D. Gagnon, J. Am. Chem. Sot., 105, 663 (1983); Schaap, S. Siddiqui, S. D. Gagnon, and L. Lopez, ibid., submi=d.
(4)
N-unsubstituted 1,2,4_dioxazolidines can be prepared by the reaction of ketones with HO andNH3: E. G. E. Hawkins, J. Chem. Sot. C, 160 (1971). See also N. Duran, J2 &-g. Chem., 2, 1791 (1974).
(5)
M. V. George has reported that direct UV irradiation of several aziridines in the presence of oxygen gave rise to products that could be rationalized in terms of lO2 addition io azomethine ylides and subsequent decomposition of intermediate 1,2,4_dioxazolidines.
(6)
(a) V. Bhat and M. V. George, Tetrahedron George, J. Org. Chem., 44, 3288 (1979).
(7)
R. N. Loeppky
(8)
The l-cm path-length filter solution was prepared from 27 g of CuSO4.5 H20, 30 g of NaN02, and 50 mL of cont. NH40H diluted with water to 1000 mL.
(9)
on Photochemistry,
Lett.,
and D. H. Smith, J. Org. Chem., s,
4133
(1977);
Pau, France,
July 26,
(b) A. P.
(b) V. Bhat and M. V.
1578 (1976).
1 cis- and trans-3,5-Diphenyl-1,2,4_trioxolanes exhibit H NMR absorptions in CDC13 for the zg protons at 6 6.331 and 6.360, respectively.3b See also: J. H. Hall, R. Huisgen, C. H. Ross, and W. Scheer, J. Chem. Sot., Chem. Commun., 1188 (1971).
(10)
R. Criegee
and H. Korber,
Chem. Ber., 104,
(11)
Evidence
(12)
(a) J. Santamaria, Tetrahedron Lett., 4511 (1981);(b) L. E. Manring, C. Gu, and C. S. Foote, J. Phys. Chem., in press. We thank Professor Foote for a preprint of this paper.
(13)
(a) H. W. Heine and R. E. Peavy, Tetrahedron Lett., 3213 (1966); (b) R. Huisgen, W. Scheer, G. Szeimies, and H. Huber, ibid., 397 (1966); (c) R. Huisgen and H. Mader, Angew. Chem., Int. Ed. Engl., 8, 604 (1969).
(14)
(a). H. W. Heine, R. H. Weese, R. A. Cooper, and A. J. Durbetaki, J. Org. Chem., 2, 2708 (1967); (b) A. Padwa and L. Hamilton, J. Heterocycl. Chem., 4,118 (1967); (c) T. DoMinh and A. M. Troszolo, J. Am. Chem. Sot., 94, 4046 (1972); (d) A. M. Trossolo, T. M. Leslie, A. S. Sarpotdar, R. D. Small, G. J. Ferraudi, T. DoMinh, and R. L. Hartless, Pure Appl. Chem., 51, 261 (1979) and references therein.
for '02 generation
(Received
in
USA
28
1807
in DCA-sensitized
February
1983)
(1971).
photooxygenations
has been reported.
12