Chemistry Reference
In-Depth Information
-NSO
2
C
6
H
4
-Me
SO
2
C
6
H
4
-Me
H
N
H
H
H
+
S
h
v >300 nm
Solvent
+
74a + 72
H
2
C
CH
2
+
H
2
C
CH
2
(CH
2
)
n
(CH
2
)
n
71a
75
n
= 1,3
SCHEME 12.35.
Photolysis of
N
-tosyliminodibenzothiophene (
71a
) in the presence of cyclic
olefins.
149
aziridines (
) were produced in good yields (57-66%
and 60-77%, respectively), indicating dibenzothiophene
N
-tosylsulfilimines have a
potent nature as nitrene sources.
149
Toscano and coworkers
26
75
) and iminophosphoranes (
76
investigated the photochemistry of
71a
, as well as
N
-mesyldibenzothiophene sulfilimine (
), using product analysis, ns TRIR spec-
troscopy and computational chemistry. Products studies from photolysis of
71b
in
alcohols and in acetonitrile in the presence of cyclohexane and
cis
- and
trans
-octene
were reported. Photolysis of
71a
71a
in CH
3
OH and 2-propanol gave exclusively amide
74a
in acetonitrile and dichloromethane in
the presence of cyclohexane (10 and 50%, respectively) gave mainly
, similar to tosyl azide. Photolysis of
71a
74
(
90-95%).
Thus, products obtained from photolysis of
differ significantly from those
obtained from photolysis and thermolysis of tosyl azide (Scheme 12.31).
Photolysis of
71a
in acetonitrile in the presence of
cis
-or
trans
-4-octene (10%)
gave a mixture of
cis
- and
trans
-aziridines with a
trans
/
cis
ration about 2 in both
cases. Raising the
cis
-4-octene concentration from 12mM to 4.3M increased the
aziridine yield from 43 to 91% and increased noticeably the retention of stereo-
chemistry. It was proposed
26
71a
71a
gives a larger portion of triplet nitrene
3
61a
forming, without participation of singlet
nitrene
1
61a
that in contrast to tosyl azide
60a
, photolysis of
, namely, from the decomposition of the triplet excited state of
71a
.
Similar to
71a
, photolysis of the mesyl derivative
71b
yielded mainly products
attributed to triplet nitrene (
3
61b
).
26
Photolysis of
71b
in CD
3
OD and 2-propanol
gave exclusively amide
in acetonitrile in the
presence of
cis
-or
trans
-4-octene (10%) gave a mixture of
cis
- and
trans
-aziridines
74a
(99-100%). Photolysis of
71a
-NSO
2
C
6
H
4
-Me
+
S
h
v >300 nm
DCE
+ R
3
P
74a + 72
+ R
3
P
NSO
2
C
6
H
4
-Me
76
71a
R = Ph, OEt, OPh
SCHEME 12.36.
Photolysis of
N
-tosyliminodibenzothiothene (
71a
) in the presence of
trivalent phosphorus compounds.
149
