Chemistry Reference
In-Depth Information
Rh
2
(
S
-DOSP)
4
CO
2
Me
Ph
CO
2
Me
Ph
N
Cbz
Ph
N
Cbz
Ph
2,2-DMB, 23°C
N
2
(2 eqv)
104
112
77% yield
93% ee
113
O
CO
2
Me
Ph
H
H
Ph
Ph
114
Scheme 4.24.
β
-Peptide synthesis via asymmetric C-H insertion of
112
.
Br
Br
Br
Br
Br
Rh
2
(
S
-DOSP)
4
N
2
N
N
CO
2
Me
MeO
2
C
CO
2
Me
60% yield
90% ee
106
115
116
Scheme 4.25.
Synthesis of
C
2
- symmetric amines.
OMe
OMe
OMe
Si
1) Rh
2
(
S
-DOSP)
4
HCl
N
HCl
2) HCl
Si
OH
N
2
N
H
2
N
CO
2
Me
CO
2
Me
62% yield
93% ee
117
118
119
120
Venlafaxine
HCl
Scheme 4.26.
Synthesis of venlafaxine.
This reaction has also been utilized in the synthesis of acyclic
C
2
- symmetric amines
(Scheme 4.25 ) [219] . Substituted
N
,
N
- dimethylanilines, here exemplifi ed by
115
, were
treated with aryldiazoacetates in excess to afford double insertion products. Product
116
was formed in 60% yield and 90% ee when the reaction was catalyzed by Rh
2
(
S
- DOSP)
4
[219]. Another synthetic application of this chemistry was shown in a short total synthesis
of the antidepressant venlafaxine (
120
, Scheme 4.26) [220]. This was achieved with the
key Rh
2
(
S
- DOSP)
4
catalyzed insertion step followed by deprotection in overall 62%
yield and 93% ee to form intermediate
119
, which was further converted to the target
120
[220] .
