Biomedical Engineering Reference
In-Depth Information
Ts
Me
Ph
N
cat. PBu
3
CH
2
Cl
2
, rt
N
Ph
Ts
•
CO
2
Et
+
CO
2
Et
7a
8a
9a
Me
Ts
Ph
N
•
CO
2
Et
PBu
3
7a
CO
3
Et
9a
Ts
C
O
2
Et
CO
2
Et
Ph
N
PBu
3
PBu
3
10
11
CO
2
Et
Ts
N
P
Bu
3
14
Ts
Ph
Ts
8a
Ph
N
Ph
NH
+
H -transfer
CO
2
Et
CO
2
Et
H -transfer
+
12
P
Bu
3
P
Bu
3
13
SCHEME 4.3
Phosphine-catalyzed [4
+
2] annulation with
N
-tosylimines. (Adapted from
[47], with permission; copyright
C
2003 American Chemical Society.)
Ts
R
1
R
2
R
1
N
cat. PBu
3
CH
2
Cl
2
, rt
R
2
N
Ts
•
CO
2
Et
+
CO
2
Et
8
7
9
SCHEME 4.4
Synthesis of highly functionalized guvacines.
TABLE 4.2 Tetra-Substituted Tetrahydropyridine
R
1
R
2
Entry
Yield (%)
cis : trans
1
H
Ph
98
2
H
4-OMe-Ph
99
3
H
4-Me-Ph
95
4
H
2-CF
3
-Ph
98
5
H
4-NO
2
-Ph
86
6
H
2-Furyl
97
7
H
4-Py
92
8
H
t
-Bu
86
a
9
Ph
Ph
99
98:2
10
4-CN-Ph
3-Cl-Ph
99
98 : 2
11
3-OMe-Ph
2-Cl-Ph
98
83 : 17
12
3-OMe-Ph
4-Me-Ph
99
98 : 2
a
3 equiv of Na
2
CO
3
was added.
