Chemistry Reference
In-Depth Information
Table 9.13
Substrate
Product
Yield (%)
R
MeO
2
C
MeO
2
C
R
OAc
O
+
MeO
2
C
MeO
2
C
R
Me
Bu
TIPS
88
82
84
Me
MeO
2
C
MeO
2
C
Me
OAc
73
O
+
MeO
2
C
MeO
2
C
R
R
OAc
TsN
O
+
TsN
R
Bu
Ph
68
75
can be applied to an
in situ
generation of highly reactive intermediates and may lead to new
activities and other possibilities. Moreover, the combination of a homogeneous catalyst and
a heterogeneous catalyst, for example a palladium complex and cobalt metal, may be a very
useful catalytic system and provide new reaction protocols that allow important building
blocks in previously unknown fashions. Recently, there has been much progress in catalytic
versions of the asymmetric PKRs. However, fine-tuning of the chiral ligands to increase
both product and optical yield is still needed. Overall, the use of heterogeneous catalysts in
the PKRs and related reactions is still a burgeoning area.
References
[1] (a) I. U. Khand, G. R. Knox, P. L. Pauson, W. E. Watts and M. I. Foreman,
Organocobalt complexes. Part II. Reaction of acetylenehexacarbonyl dicobalt com-
plexes (R
1
C
2
R
2
)Co
2
(CO)
6
, with norbornene and its derivatives,
J. Chem. Soc. Perkin
Trans
.
1
977 (1973); (b) V. Rautenstrauch, P. Megard, J. Conesa and W. Kuster,
2-Pentylcyclopent—2-en-1-one by catalytic Pauson-Khand reaction,
Angew. Chem.
Int. Ed. Engl.
29
, 1413 (1990)
[2] (a) N. Jeong, S. H. Hwang, Y. S. Lee and Y. K. Chung, Catalytic conversion of
the intramolecular Pauson-Khand reaction,
J. Am. Chem. Soc.
116
, 3159 (1994); (b)
