Chemistry Reference
In-Depth Information
R
1
X
Rh(CO D)
2
OTf (5 mol %)
(
R
)-Cl,MeO -BIPHEP (5 mol %)
X
R
1
Y
Y
2-Naphthoic acid (5 mol %)
H
2
(1 atm)
Dichloroethane, 45°C
R
2
OH
R
2
R
2
O
R
2
67
66
Ph
Ph
TsN
O
O
OH
TsN
p
-BrBnN
Bn N
OH
Me
Me
OH
OH
67a,
85%, 97% ee
67b
, 67%, 95% ee
67c
, 99%, 91% ee
67d
,77%,91%ee
Me
Me
Me
Me
Me
O
TsN
O
TsN
OH
OH
OH
Me
Me
Me
Me
OH
67e
, 76%, 96% ee
67f
, 63%, 98% ee
67g
,86%,99%ee
67h
,73%,99%ee
Scheme 8C.27.
O
[Rh(COD)Cl]
2
(2.5 mol %)
Ligand (7.5 mol %)
HO
Me
O
O
Ph
Ph
Me
PhB(OH)
2
(200 mol %)
H
2
O(500mol %)
Dioxane (0.1M), 95°C
Ph
68a
69a
%ee
Ligand
Yield (%)
62
77
87
88
(
R
)-tol-BINAP
(
R
)-BINAP
(
R
)-BINAP
a
(
R
)-BINAP
b
94
90
80
88
a
TEA (1000 mol %) was added.
b
Rh(C
2
H
4
)
2
(acac) was used as catalyst, and KOH (10 mol %) was added.
Scheme 8C.28.
This methodology was applied to the enantioselective desymmetrization of enone-
diones
72
. This reaction gave rise to fused bicyclic products
73
, embodying four contigu-
ous stereocenters, with excellent stereochemical control (Scheme 8C.30) [56]. The
products
73
would serve as synthons to implement contiguous chiral centers in the total
synthesis of both natural and unnatural compounds of medicinal interest.
To extend the scope of this reaction, the feasibility of Cu-catalyzed conjugate addi-
tion-aldol cyclization process was investigated. Cu-catalyzed addition of organozinc
