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The photolysis of β-ketosulphones: An intramolecular rearrangement
Tetrahedron Letters ITo.1,pp. 37-42, 1967. Pergamon Press Ltd. Printed in Great Britain.
THE PHOTOLYSIS
OF S-KETOSULPHONES:
AN INTRAMOLECULAR
C.L. Department
McIntosh,
P.
of Chemistry,
REARRANGEMENT
de Mayo and R. University
London,
W. Yip
of Western
Ontario,
Canada.
(Received 10 October 1966) Sulphenes, mediates
RR’C
by Wedekind
=SO,,
were first
existence
z
highly probable.
need for a method of preparation aprotic
conditions.
ing a hydrogen route:
gen of the excited would produce
This
several
of simple
The ultraviolet
of the y hydrogen carbonyl
group,
studies
no stable 3
sulphenes
irradiation
and still is,
under neutral
atom,
seemed
atom by the electron followed
substance
of S-ketosulphones 4
by Norrish
is Photochemical
Syntheses,
bear-
a possible
deficient
oxy-
Type II cleavage
a sulphene.
communication
inter-
have made their
There was, however,
atom attached to the y-carbon
abstraction
as chemical
and Schenk in 1911. ’ Although
of this type has yet been isolated, transient
suggested
Part 14.
a
No.1
MeOH ----,R-CH \ CHz
R- CH-SO,
HO-Cd
= SO,-
RI-C \ R
R Bensyl
acetonyl
R CHrSOaMe
+ = CH,
I
OH
sulphone,
I, and bensyl 596
prepared
were
from
and II in methanol
the corresponding
at 0 ‘,
gave a mixture
the N. M.R.
spectra
separation
by thin layer
chromatography
for methyl
a-toluene
I.
Neither
using an immersed
(0.75$,
arc and a Corex filter
sulphene
sulphonate
This had previously
).
sulfides.
sulphone. II.
Irradiation
of both I
Hanovia 450 watt mercury of products
of the reaction
( from
phenacyl
as shown in Table
product
mixtures,
gave any evidence
nor
of the hoped
the addition of methanol
to the
been shown to be stable under the irrad-
iation conditions. It was clear the result
of cleavage
that all the products
of the carbon-sulphur
group without any commitment B -C-CHrOSO,volved.
hv ___+
The radicals
_&Q-
for the case of the acetonyl onate was of particular stances from
appeared
the phenacyl
of the styryl
compound.
is probably
as
in-
9 -C = CH, +SO,_
The formation
as shown below of the vinyl sulph-
since only two syntheses
to have been recorded.
product.
of the species
2 -v could then react further,
interest
derivative
M
could have arisen
bond beta to the carbonyl
as to the multiplicity
So,-
formed
formed
The absence to be attributed
for these
sub-
of such an ester to the reactivity
No.1
39
CHsGOCH,
Q=W’z J CHsCOCH,.
But it appeared formed
by the Norrish
of the so-formed
possible,
that the vinyl ester
Type II cleavage,
followed
ical combination,
to distinguish
t-hutyl
ed from the sulfide
9
cage.
between this possibility
acetonyl
in a similar
could have been
by rapid recombination
sulphene and enolic ketone in a solvent
In order
instead
8 CHsSO,.
sulfone, manner,
III, h.p.
and that of rad-
106- 108O was PrePar-
but using 30$H,O,
in acetic
acid
of KMn04. Irradiation
product
mixture
the mixture hydrogen
shown in Table 1.
excluded
atoms
of III under the same
the Norrish
available
conditions
The presence
gave a
of the vinyl sulphonate
Type II mechanism
for abstraction.
as before,
since III has no8
in
No.1
40
TABLE I ($: Isolated)
Yield R.SO,H
R-R
RCHaCOR
CH,COR’
R= C&.CH, R’=Me
44a
22
13
59b
R= C&CH, R’ = C6Hs
22c
24
78
R=(CH,),C R’ =Me(f)
28
(d)
56
RSO,CH,COR’
+&Hz RSO,C \ R’
be
168
chrom(a) Identified as acid and methyl ester; (b) estimated by gas-liquid atography and identified as the 2,4_dinitrophenylhydrazone: (c) characterised as the methyl ester; (d) 164 of the sulphonic ester was obtained; (e) N.M.R.: 0 1.87 (s,3H), 4.34 (s,2H), 4.74 (2H) doublet of doublets, JAB= 2.0
OB-“A’
7.8
c.p.s.,
7.40
(s,5H);
tiax
1670,
1365,
1167,
953 cm.-‘;
(f) N.M.R. 0 1.36 (s,9H), 2.38 (s,3H), 3.96 (s,ZH); x.max E200 = 3,000: 1720, 17 13, I 112 cm-‘; ~2~~ = 2,000; 2,4_dinitrophenylhydrazone; m.p. 171a 1.46(s,9H), 2.02 (s,3H), 4.80 (2H) doublet of doublets 172O, N.M.R. $-aA= 10.7 =.p.s.; 1668, 1345, 1149, 951 cm-i; tZOO = hax JAB = 2.0, 2,400. The process cially,
of formation
to be related
of the vinyl
to that of a family
sulphonates
of reactions
appeared,
involving
superfi-
the intercon-
esters, and lactones ‘o-‘4 for which a rad15 ical pathway had been suggested . However, a third, intramolecular ,
versions
of P-diketones,
pathway rejected formation
enolic
for these
ify any solvent
mains
, remained to be considered
of the effects
cage are shown.
of oxygen,
essentially
contrast,
15
for the
of the vinyl sulphonates.
In Table II, the results
an excess
reactions
seriously
Under a variety
the yield of ester
constant. affected.
of attempts
estimated
The proportions In benzene,
to penetrate
of conditions, from
including
N. M.R.
of other components
for instance,
or mod-
spectra are,
no sulphinic
rein
acid
No .l
41
is formed
(no hydrogen
easily
sence of oxygen all the benzyl
available radicals
for extraction)
whilst
are trapped before
in the pre-
dimerisation,
or ketone formation. It thus appears sulphonates,
that the process
if it occurs
the molecules
yl radicals
in a solvent
constituting
gen cannot intervene. do escape
This evidence
leading
that cage,
Yet,
cage,
renders
is independent
and that external
nonetheless,
to undergo
to the formation
of the vinyl
of the nature of
agents
a constant fraction
such as oxyof the sulphon-
other transformations.
radical
combination
a less
engaging rational-
16
isation
whilst that of an intramolecular
expansion
of the sulphur
shell,
composition
Solvent
Additive
(g CH2)z
MeOHa
-
31
MeOHa
C&(lO%w/v)
MeOHa C6H6
Oz
a.b.
MeOHC
(a) Estimated ester.
involving
a wild surmise.
II from
the irradiation
q GHaSOaH q CHaSOaCsH,
of I at O”
g CHsCHsCOCHs
11
12
9
None
11
5
None
8a
13
Trace
_
40
None
10
32
_
22
44
6
13
Diisogropylether EtOH(95$)=
process,
need not now be deemed TABLE
Product
four-centre
6 7
yields
from
N.M.R.
(b) loo (c) Isolated
yields
(d) Sulphonic
No.1
42
The authors
are indebted to the National
and the Squibb Institute are very F.
for Medical
glad to acknowledge
Research
Research
several
Council of Canada
for financial
stimulating
support,
discussions
and
with Dr.
J.
King. REFERENCES
1.
E.
Wedekind
and D. Schenk,
2.
Recently there has been report of the stability of a complex sulphene at -40° (G. Opitz, M. Kleeman, D. Bucher, G. Walz and K. Rieth, Angewandte Chem. Internat. Edit., 5, 594 (1966). --=
3.
For leading references, see J.F. King and T. Durst, J. Am. Chem. Sot. 87, 5684 (1965): W.E. Truce and R. W. Campbell: IbK 88,99 -(1966r
4.
The only previously reported irradiation of p keto sulfone is that of R.B. LaCount and C.E. GriffidTetrahedron Letters, 1549. (1965)] who noted the formation of dibenzyl and didesyl.
5.
C. Wahl,
Bs.,
6.
Adequate
analyses
7.
J. C.
8.
A.N. Nesmeyanov, I.F. ovitskii, J. Gen. Chem. -
9.
C.K. Bradsher, F. C. Brown, e. 2, 114 (1954).
22, -
-Ber.
42, -
(1911).
1449 (1922). have been obtained for all new compounds
Sauer and J. D. C.
Wilson,
I. &
w
Lutsenko, R.M. 2, 2776 (1959).
Spy. 12, -
Khomutov,
and R.J.
Grantham,
J. Am. --
M. Feldkimel-Gorodetsky, (1963).
and Y.
Mazur,
Tetrahedron
11.
A. Yogev, M. 5208 (1964).
and Y.
Mazur,
J. Am. ---
12.
A.
13.
R. C. Cookson, A.G. Comm. 98 (1965).
14.
Yogev,
H. Nozaki,
and Y.
Z.
Mazur,
J. Am. ---I_
Edwards,
Yamaguti,
Chem.
J. Hudec,
and R.
Noyori,
Sot.
3793 (1955).
and V.A.
IO.
Gorodetsky,
Dub-
-Chem.
Letters,
Chem.
2,
reported.
Sot. --
369
86,
3520 (1965).
and M.
Kingsland,
Tetrahedron
Chem.
Letters,
37
(1965). 15.
M.
16.
This must be interpreted with caution since it has been shown a solvent as reactive as bromine may be necessary to intercept ical pair.
17.
Gorodetsky
and Y.
Mazur,
J_. -Am.
Chem. ---
Sot.
-
86,
52 13 (1964). 17
0. D. (1959).
Trapp and G. S. Hammond,
J.Am. ---
Chem.
Sz
,&, -
4876
that a rad-
THE PHOTOLYSIS
OF S-KETOSULPHONES:
AN INTRAMOLECULAR
C.L. Department
McIntosh,
P.
of Chemistry,
REARRANGEMENT
de Mayo and R. University
London,
W. Yip
of Western
Ontario,
Canada.
(Received 10 October 1966) Sulphenes, mediates
RR’C
by Wedekind
=SO,,
were first
existence
z
highly probable.
need for a method of preparation aprotic
conditions.
ing a hydrogen route:
gen of the excited would produce
This
several
of simple
The ultraviolet
of the y hydrogen carbonyl
group,
studies
no stable 3
sulphenes
irradiation
and still is,
under neutral
atom,
seemed
atom by the electron followed
substance
of S-ketosulphones 4
by Norrish
is Photochemical
Syntheses,
bear-
a possible
deficient
oxy-
Type II cleavage
a sulphene.
communication
inter-
have made their
There was, however,
atom attached to the y-carbon
abstraction
as chemical
and Schenk in 1911. ’ Although
of this type has yet been isolated, transient
suggested
Part 14.
a
No.1
MeOH ----,R-CH \ CHz
R- CH-SO,
HO-Cd
= SO,-
RI-C \ R
R Bensyl
acetonyl
R CHrSOaMe
+ = CH,
I
OH
sulphone,
I, and bensyl 596
prepared
were
from
and II in methanol
the corresponding
at 0 ‘,
gave a mixture
the N. M.R.
spectra
separation
by thin layer
chromatography
for methyl
a-toluene
I.
Neither
using an immersed
(0.75$,
arc and a Corex filter
sulphene
sulphonate
This had previously
).
sulfides.
sulphone. II.
Irradiation
of both I
Hanovia 450 watt mercury of products
of the reaction
( from
phenacyl
as shown in Table
product
mixtures,
gave any evidence
nor
of the hoped
the addition of methanol
to the
been shown to be stable under the irrad-
iation conditions. It was clear the result
of cleavage
that all the products
of the carbon-sulphur
group without any commitment B -C-CHrOSO,volved.
hv ___+
The radicals
_&Q-
for the case of the acetonyl onate was of particular stances from
appeared
the phenacyl
of the styryl
compound.
is probably
as
in-
9 -C = CH, +SO,_
The formation
as shown below of the vinyl sulph-
since only two syntheses
to have been recorded.
product.
of the species
2 -v could then react further,
interest
derivative
M
could have arisen
bond beta to the carbonyl
as to the multiplicity
So,-
formed
formed
The absence to be attributed
for these
sub-
of such an ester to the reactivity
No.1
39
CHsGOCH,
Q=W’z J CHsCOCH,.
But it appeared formed
by the Norrish
of the so-formed
possible,
that the vinyl ester
Type II cleavage,
followed
ical combination,
to distinguish
t-hutyl
ed from the sulfide
9
cage.
between this possibility
acetonyl
in a similar
could have been
by rapid recombination
sulphene and enolic ketone in a solvent
In order
instead
8 CHsSO,.
sulfone, manner,
III, h.p.
and that of rad-
106- 108O was PrePar-
but using 30$H,O,
in acetic
acid
of KMn04. Irradiation
product
mixture
the mixture hydrogen
shown in Table 1.
excluded
atoms
of III under the same
the Norrish
available
conditions
The presence
gave a
of the vinyl sulphonate
Type II mechanism
for abstraction.
as before,
since III has no8
in
No.1
40
TABLE I ($: Isolated)
Yield R.SO,H
R-R
RCHaCOR
CH,COR’
R= C&.CH, R’=Me
44a
22
13
59b
R= C&CH, R’ = C6Hs
22c
24
78
R=(CH,),C R’ =Me(f)
28
(d)
56
RSO,CH,COR’
+&Hz RSO,C \ R’
be
168
chrom(a) Identified as acid and methyl ester; (b) estimated by gas-liquid atography and identified as the 2,4_dinitrophenylhydrazone: (c) characterised as the methyl ester; (d) 164 of the sulphonic ester was obtained; (e) N.M.R.: 0 1.87 (s,3H), 4.34 (s,2H), 4.74 (2H) doublet of doublets, JAB= 2.0
OB-“A’
7.8
c.p.s.,
7.40
(s,5H);
tiax
1670,
1365,
1167,
953 cm.-‘;
(f) N.M.R. 0 1.36 (s,9H), 2.38 (s,3H), 3.96 (s,ZH); x.max E200 = 3,000: 1720, 17 13, I 112 cm-‘; ~2~~ = 2,000; 2,4_dinitrophenylhydrazone; m.p. 171a 1.46(s,9H), 2.02 (s,3H), 4.80 (2H) doublet of doublets 172O, N.M.R. $-aA= 10.7 =.p.s.; 1668, 1345, 1149, 951 cm-i; tZOO = hax JAB = 2.0, 2,400. The process cially,
of formation
to be related
of the vinyl
to that of a family
sulphonates
of reactions
appeared,
involving
superfi-
the intercon-
esters, and lactones ‘o-‘4 for which a rad15 ical pathway had been suggested . However, a third, intramolecular ,
versions
of P-diketones,
pathway rejected formation
enolic
for these
ify any solvent
mains
, remained to be considered
of the effects
cage are shown.
of oxygen,
essentially
contrast,
15
for the
of the vinyl sulphonates.
In Table II, the results
an excess
reactions
seriously
Under a variety
the yield of ester
constant. affected.
of attempts
estimated
The proportions In benzene,
to penetrate
of conditions, from
including
N. M.R.
of other components
for instance,
or mod-
spectra are,
no sulphinic
rein
acid
No .l
41
is formed
(no hydrogen
easily
sence of oxygen all the benzyl
available radicals
for extraction)
whilst
are trapped before
in the pre-
dimerisation,
or ketone formation. It thus appears sulphonates,
that the process
if it occurs
the molecules
yl radicals
in a solvent
constituting
gen cannot intervene. do escape
This evidence
leading
that cage,
Yet,
cage,
renders
is independent
and that external
nonetheless,
to undergo
to the formation
of the vinyl
of the nature of
agents
a constant fraction
such as oxyof the sulphon-
other transformations.
radical
combination
a less
engaging rational-
16
isation
whilst that of an intramolecular
expansion
of the sulphur
shell,
composition
Solvent
Additive
(g CH2)z
MeOHa
-
31
MeOHa
C&(lO%w/v)
MeOHa C6H6
Oz
a.b.
MeOHC
(a) Estimated ester.
involving
a wild surmise.
II from
the irradiation
q GHaSOaH q CHaSOaCsH,
of I at O”
g CHsCHsCOCHs
11
12
9
None
11
5
None
8a
13
Trace
_
40
None
10
32
_
22
44
6
13
Diisogropylether EtOH(95$)=
process,
need not now be deemed TABLE
Product
four-centre
6 7
yields
from
N.M.R.
(b) loo (c) Isolated
yields
(d) Sulphonic
No.1
42
The authors
are indebted to the National
and the Squibb Institute are very F.
for Medical
glad to acknowledge
Research
Research
several
Council of Canada
for financial
stimulating
support,
discussions
and
with Dr.
J.
King. REFERENCES
1.
E.
Wedekind
and D. Schenk,
2.
Recently there has been report of the stability of a complex sulphene at -40° (G. Opitz, M. Kleeman, D. Bucher, G. Walz and K. Rieth, Angewandte Chem. Internat. Edit., 5, 594 (1966). --=
3.
For leading references, see J.F. King and T. Durst, J. Am. Chem. Sot. 87, 5684 (1965): W.E. Truce and R. W. Campbell: IbK 88,99 -(1966r
4.
The only previously reported irradiation of p keto sulfone is that of R.B. LaCount and C.E. GriffidTetrahedron Letters, 1549. (1965)] who noted the formation of dibenzyl and didesyl.
5.
C. Wahl,
Bs.,
6.
Adequate
analyses
7.
J. C.
8.
A.N. Nesmeyanov, I.F. ovitskii, J. Gen. Chem. -
9.
C.K. Bradsher, F. C. Brown, e. 2, 114 (1954).
22, -
-Ber.
42, -
(1911).
1449 (1922). have been obtained for all new compounds
Sauer and J. D. C.
Wilson,
I. &
w
Lutsenko, R.M. 2, 2776 (1959).
Spy. 12, -
Khomutov,
and R.J.
Grantham,
J. Am. --
M. Feldkimel-Gorodetsky, (1963).
and Y.
Mazur,
Tetrahedron
11.
A. Yogev, M. 5208 (1964).
and Y.
Mazur,
J. Am. ---
12.
A.
13.
R. C. Cookson, A.G. Comm. 98 (1965).
14.
Yogev,
H. Nozaki,
and Y.
Z.
Mazur,
J. Am. ---I_
Edwards,
Yamaguti,
Chem.
J. Hudec,
and R.
Noyori,
Sot.
3793 (1955).
and V.A.
IO.
Gorodetsky,
Dub-
-Chem.
Letters,
Chem.
2,
reported.
Sot. --
369
86,
3520 (1965).
and M.
Kingsland,
Tetrahedron
Chem.
Letters,
37
(1965). 15.
M.
16.
This must be interpreted with caution since it has been shown a solvent as reactive as bromine may be necessary to intercept ical pair.
17.
Gorodetsky
and Y.
Mazur,
J_. -Am.
Chem. ---
Sot.
-
86,
52 13 (1964). 17
0. D. (1959).
Trapp and G. S. Hammond,
J.Am. ---
Chem.
Sz
,&, -
4876
that a rad-