Chemistry Reference
In-Depth Information
AgNO
3
n
-C
7
H
15
n
-C
5
H
11
n
-C
5
H
11
O
n
-C
7
H
15
HO
6.190
6.191
n
-C
5
H
11
O
n
-C
7
H
15
6.192
Scheme 6.74
O
N
AuCl
3
S
O
6.194
H
S
O
6.193
Ph
3
PAu N T f
2
N
S
6.155
Scheme 6.75
F
F
F
F
F
AuCl
3
, CH
3
CN
Ar
R
R
Ar
Ar
N
N
TsHN
R
Ts
Ts
6.156
6.157
6.158
Scheme 6.76
n
-C
11
H
23
NH
2
NaAuCl
4
H
n
-C
11
H
23
n
-C
11
H
23
N
6.159
6.160
6.161
Scheme 6.77
catalyst, migration was not observed, giving the
exo
-cyclic isomer
6.155
. The reactive
exo
-cyclic double bond
opens up synthetic possibilities to introduce further functionality.
Alternatively, cyclization can be followed by elimination to give the aromatic heterocycle (Scheme 6.76).
With two fluorine substituents in the starting material
6.156
, only one is eliminated from intermediate
6.157
,
leading to a 3-fluoropyrrole
6.158
.
82
In a pioneering example, an amino alkyne
6.159
cyclized in the presence of a gold(III) salt to give an
unstable
exo
-cyclic enamine
6.160
, which tautomerized to the tetrahydropyridine
6.161
, a component of an
ant venom (Scheme 6.77).
83
