Laureates: awards and Honors, sCs FaLL Meeting 2011
CHIMIA 2012, 66, No. 4 243
Piv
O
Cs
3
H
Piv
O
H
Br
N
[Pd(η -cinnamyl)Cl] (2.5 mol% )
3
2
1/2 [Pd(η -cinnamyl)Cl]
2
3
+
Pd(N
H
C)(η -cin
n
a
myl)I
NHC·HI 9 (5 mol% )
NHC·HI
CsCl
n
Piv Cs
O
n
Cs2CO3 (1.5 equivs.),
N
H
CO2Me
tBuCO2Cs (1 equiv.),
Ph
OPiv
CsI
CO2Me
mesitylene, 160 °C,3h
Pd(0)-N
HC
H
Br
N
H
H
H
N
H
O
OMe
O OMe
2a
1a
NHC
Pd
N
H
C
Br
O
H
Pd
N
CO2Me
N
CO2Me
N
CO2Me
H
H
H
N
OMe
N
H
2a
2n
2o
O
OMe
78%, 90% ee
0% (24 h)
94%, 95% ee
CsHCO3
PivOCs
Scheme 4. Effect of alkane ring size in asymmetric synthesis of fused
indolines.
NHC OPiv
Piv
O
H
Cs2CO3
Pd
O
N
OMe
CsBr
PivOH
Scheme 5. Plausible catalytic cycle in asymmetric fused indoline synthe-
sis
fused indoline containing natural products: a)
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Oxidative addition of carbamate 1a forms
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by bromide ligand exchange for piva-
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one only of the two enantiotopic C(sp3)–H
enters the reaction to give the trans-fused
product selectively and regeneration of a
Pd(0)-NHC species.
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H. Hansen, T. M. Gregg, S. R. Ovalles, Y. Lian,
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indolines is in progress.
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Acknowledgements
8484; b) Y.-X. Jia, J. M. Hillgren, E. L. Watson,
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We gratefully acknowledge the University
of Geneva and the Swiss National Science
Foundation for the financial support.
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[6] Selected recent examples of the synthesis of