Chemistry Reference
In-Depth Information
TABLE 12.2. Irradiation of 2-Naphthoyl Azide 7 in Cyclohexane Containing Various
Nitrene Trapping Reagents
Product Yields (Absolute %)
Isocyanate
8
Amide
9
Amide
10
Aziridine
Trapping Reagent (M)
11
12a
12b
None
N
2
saturated
54
44
Trace
O
2
saturated
54
45
Trace
Laser irradiation
58
41
Trace
Cyclohexene
0.3
53
Trace
Trace
36
0.03
49
22
Trace
26
0.003
52
44
Trace
8
cis
-4-Methyl-2-pentene
0.2
52
Trace
ND
46
ND
0.05
54
16
ND
32
ND
0.01
52
34
ND
17
ND
0.01 (O
2
sat.)
53
33
ND
16
ND
trans
-4-Methyl-2-pentene
0.67
53
9
ND
36
0.05
53
39
1
ND
4
Trace, the yield is
<
1%; ND, no peak was detected by HPLC.
51
less that 2%).
24b
1b
in
trans
-4-methyl-2-pentene gives a
In contrast, photolysis of
14b
15b
in about 14% yield (
cis
to
trans
complex mixture containing both
and
1:4) (Scheme 12.7).
24b
Similar results were obtained by Lwowski and coworkers.
68,70
Photolysis of
1b
in
the mixtures of dichloromethane and
cis
-4-methyl-2-pentene gives exclusively
cis
-
aziridine
ratio
ΒΌ
. In comparison, photolysis in dichloromethane/
trans
-4-methyl-2-
pentene mixture gave both
trans
- and
cis
-aziridines (
14b
15b
and
14b
). The yield of
15b
increased from 7.4% to 20.5%, by decreasing of the olefin concentration from
78% to 3%. The yield of
14b
is approximately the same (5.6
0.5%) over the same
O
O
O
R
1
h
v
H
H
H
CH
3
+
+
(H
3
C)
3
C
N
3
(H
3
C)
3
C
N
(H
3
C)
3
C
N
R
2
1b
14b
15b
H
CH
3
cis
: R
1
= CH
3
, R
2
= H
trans
: R
1
= H, R
2
= CH
3
SCHEME 12.7.
Photolysis of pivaloyl azide
1b
in the presence of
cis
-4-methyl-2-pentene or
trans
-4-methyl-2-pentene.
24b,68,70
