Chemistry Reference
In-Depth Information
R
1
R
1
R
1
R
2
R
2
R
2
PIFA
or
Ag(I)
or
O
O
O
HTIB
Zn(II)
X
X
X
N
n
N
n
N
n
322
Cl
H
321
323
Ar
1
-n
Ar
2
-n
R
1
O
R
2
R
2
H
2
O
H
1,2-Shift
n
X
X
R
1
= H
R
2
N
O
N
N
X
n
n
O
O
325
326
324
n
= 0, 1, 2
R
2
= H, OR, F, Cl
alkyl, NHCOR
n
= 0, 1, 2, 3
R
2
= OR, NO
2
F, Br
X = OMe, NPhth
R
1
= OMe, H
F, Cl, Br
SCHEME 10.50.
position of
330
would generate the 7-methoxy derivative:
332
clearly arises by a 1,2-
carbon migration.
103b
The reactions of
O-
alkyl chlorohydroxamates of general structure
333
, in which
the arene is housed within the alkoxy, rather than the acyl side-chain have been
studied in detail by Glover
et al.
(Scheme 10.52).
103,125
In common with
O
-alkyl
PIFA
PIFA
O
H
N
N
O
HN
O
TFE
HFIP
NPhth
CF
3
CH
2
O
NPhth
NPhth
328
(73%)
329
(76%)
327
MeO
AgBF
4
6
7
O
N
MeO
N
O
N
O
Cl
Et
2
O
O
OMe
OMe
OMe
330
331
(9%)
332
(13%)
SCHEME 10.51.
