Chemistry Reference
In-Depth Information
Tab l e 7 . 3
A summary of rhodium catalysts and their activities.
Inter-
Intra-
p
(CO)
Entry
PKR
PKR
Catalyst system
[atm]
TON
a
Ref.
X
√
1
[Rh(dppp)
2
Cl]
b
0
(11-20)
16
X
√
2
[Rh(dppp)
2
Cl]
c
0
(7-10)
15
X
√
3
[Rh(COD)Cl]
2
+
(
S
)-P-Phos
c
0
(8-15)
24
X
√
4
[Rh(COD)Cl]
2
+
(
S
)-BisbenzodioxanPhos
c
0
(10-16)
25
X
√
5
[Rh(COD)Cl]
2
+
(
S
)-xyl-BINAP
d
0
(1-7)
32
X
√
6
[Rh(COD)Cl]
2
+
dppp
e
0
(3-15)
37
X
√
7
[Rh(COD)Cl]
2
+
dppp
f
0
(3-7)
36
X
√
8
[Rh(COD)Biphemp]X
g
X
=
BF
4
−
,PF
6
−
,OTf
−
0
(16-25)
8
X
√
9
[Rh(COD)Cl]
2
+
dppp
+
TPPTS
+
SDS
h
0
(6-9)
20
√
10
X
[Rh(COD)Cl]
2
i
5
(7-9)
6
√√
[Rh(CO)
2
Cl]
2
11
1
(4-6) (7-28)
5
√
12
X
[Rh(CO)
2
Cl]
2
+
(
R
)-SIPHOS
1
(5-12)
13
√
[Rh(CO)(dppp)Cl]
2
j
13
X
1
(7-15)
38
√
14
X
[Rh(CO)
2
Cl]
2
+
(
S
)-BINAP
1
(6-16)
4
√
[Rh(CO)
2
Cl]
2
k
15
X
1
(3-10)
9
a
TONs calculated with respect to the number of moles of Rh
1
, TONs in parentheses are turnover numbers of intramolecular
PKR
b
Using pentafluorobenzaldehyde as CO source
c
Using cinnamaldehyde as CO source under conventional heating
d
Using benzylformate as CO source under conventional heating
e
Using cinnamaldehyde as CO source under microwave irradiation
f
Using p-chlorobenzylformate as CO source under microwave irradiation
g
Using 4 A M.S. entrapped with CO
h
Using formaldehyde as CO source in aqueous medium
i
Rh catalyst entrapped by silica-sol gel
j
Under an (Ar:CO) atmosphere, demonstrating the effects of CO pressure on product yields
k
Under 1 atm (Ar:CO
=
10:1) atmosphere
Intramolecular Ir-catalyzed PKR
R'
Ph
10 mol% [Ir(cod)Cl]
2
R'
20 mol% (
S
)-tol-BINAP
Z
R
Z
O
O
O
Toluene, reflux
CO (1 atm)
*
*
R
Me
R=HorMe
R' = aryl, alkyl
Z = O, NTs, C(COOEt)
2
CO (1 atm): 88%
ee
(30% yield)
CO (0.2 atm): 93%
ee
(86% yield)
82-98%
ee
51-85% yield
Intermolecular Ir-catalyzed PKR
O
O
10 mol% [Ir(cod)Cl]
2
20 mol% (
S
)-tol-BINAP
Ph
Me
+
+
Ph
Me
Toluene, reflux
CO (1 atm)
Me
Ph
A
93%
ee
B
Excess
32% yield (
A:B
=>10:1)
Scheme 7.25
Asymmetric Ir-catalyzed intra- and intermolecular PKR.
