Chemistry Reference
In-Depth Information
Me
Me
Me
Me
Me
Me
Me
Me
h
v
MeOH
Me
Me
Me
+
NH
Me
P
Me
N
3
P
P
NH
2
Me
O
OMe
O
O
84
(16%)
OMe
85
(60%)
82
SCHEME 12.39.
Photolysis of 1-azidophosphetan oxide
82
.
156
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
h
v
MeOH
+
+
NH
Me
Me
NH
P
Me
N
3
P
P
P
NH
2
O
O
OMe
O
87
(~20%)
OMe
O
88
(13%)
OMe
86
(~20%)
83
SCHEME 12.40.
Photolysis of 1-azidophosphetan oxide
83
.
156
gave products resulting from loss of nitrogen and ring opening or ring expansion
(Schemes 12.39 and 12.40). The ring expansion products (
) are products of a
formal insertion of a singlet nitrene into a CP bond followed by the addition of
methanol to a double P
85-87
)
could be interpreted as a triplet nitrene reaction of hydrogen abstraction from a
methyl group, which is accompanied by the CP bond dissociation.
Harger and Westlake studied photolysis of a series of diaryl
157a
and alkylphe-
nylphosphinyl azides.
157b,c
Photolysis of the diarylphosphinyl azides Ar
2
P(O)N
3
(Ar
N bond. Formation of the ring opening products (
84
and
88
phenyl,
p
-tolyl,
p
-anisyl-,
p
-chlorophenyl) in methanol gave as the final
products the methyl NP-diarylphosphonamidate (
ΒΌ
89
, 41-53%), diarylphosphinyl
amide (
90
, 18-42%), and small amount of
the
N
-methoxy compound
91
(Scheme 12.41).
157a
The phosphonamidates
89
form in a reaction between methanol
and a Curtius-like rearrangement products
that arises either in a concerted fashion
with the loss of N
2
or from the singlet nitrene.
157,158
92
O
Ar
O
Ar
O
h
v
Ar
P
+
P
P
-N
2
92
NAr
78
Ar
N
3
Ar
N
80
CH
3
OH
CH
3
OH
Ar
O
Ar
O
Ar
O
P
P
P
MeO
NHAr
Ar
NH
2
Ar
NHOMe
90
91
89
SCHEME 12.41.
Products of photolysis of diarylphosphinyl azides in methanol (new
version).
157a
