Biomedical Engineering Reference
In-Depth Information
H
H
(Ph
3
P)AuOTf (10 mol%)
DBU, BF
3
.OEt
2,
CH
2
Cl
2
,r
t
O
O
OH
O
O
OAc
H
H
O
O
BnO
n
-Bu
HO
HO
H
H
O
AcO
OBn
BnO
OBn
72%
OBn
(Ph
3
P)AuOTf (20 mol%)
CH
2
Cl
2
, -78°C to rt
OBn
OBn
O
O
H
H
BnO
BnO
(Ph
3
P)AuOTf
O
O
BnO
(37 mol%)
BnO
O
O
O
H
O
H
AcO
BnO
O
AcO
O
BnO
O
H
O
OH
H
O
n
-Bu
O
O
BnO
OTBDPS
BnO
O
BzO
OBn
BzO
O
OBn
BnO
BnO
OBn
OBn
OTBDPS
60% (2 steps)
OPMB
1. DBU, MeOH
CH
2
Cl
2
,rt
BnO
O
2. (Ph
3
P)AuOTf
(20 mol%)
CH
2
Cl
2
,rt
97%
BnO
O
O
n
-Bu
H
H
HO
BnO
O
O
steps
HO
BnO
O
O
O
O
H
H
BnO
O
O
HO
O
O
OBz
OH
H
H
HO
O
BnO
O
O
O
O
O
HO
OH
BnO
OBn
O
O
HO
O
O
BnO
OH
OBn
O
PMBO
O
OTBDPS
OH
OBn
249
SCHEME 4.71a
is rather singular as the reactivity and the selectivity they show are usually higher than
that of othermetallic sources, such as palladium, silver, ormercury. Themildness of the
reaction conditions is another point of importance as some transformations that can be
classically carried out under thermal conditions can be performed at room temperature
under gold-catalyzed conditions (see the synthesis of azadirachtin (Section 4.5)).
Despite the exemplified wide applicability of gold-mediated catalysis, it should be
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