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R
R'
R
R'
Pd(PPh
3
)
4
(1 equiv)
CO (1 .1 atm)
NEt
3
(1.1 equi v)
THF, 60
o
C, 1 8-24 h
I
O
R=n-Hex;R'=SiMe
3
R=Me;R'=Me
54%
51%
Scheme 10.1 The first examples of palladium-mediated intramolecular carbonyla-
tive Heck reactions.
I
I
I
I
Me
3
Si
I
n
-He x
n
-Hex
n
-Hex
1a
1b
1c
1d
1e
CO
2
Me
CO
2
Me
O
O
O
MeO
2
C
O
CO
2
Me
O
Me
3
Si
CO
2
Me
n
-Hex
n
-Hex
n
-Hex
90%
75% 66 % 67%
58 %
Pd Cl
2
(PP h
3
)
2
(5mol%), CO (41 bar), NEt
3
(1 .5 equiv), MeOH (4 equi v), 10 0
o
C, C H
3
CN-ben zene , 18-24 h
O
O
Pd(PPh
3
)
4
(1 e quiv), NE t
3
(1.5 equiv)
55
o
C, 1 h, CH
3
CN-benzene
Cl
1f
1g
50%
Scheme 10.2 Pd-catalysed intramolecular carbonylative Heck reactions.
the presence of MeOH. The corresponding products were obtained in mod-
erate to excellent yields (Scheme 10.2). A possible reaction mechanism was
proposed and ''CO-free'' carbonylative Heck reactions were realized. 2-Meth-
ylene-2,3-dihydroinden-1-one (1g) was produced from the corresponding acid
chloride 1f in 50% yield under ''CO-free'' conditions (Scheme 10.2).
Negishi's group continued their interest in this topic by synthesizing
various quinones from o-iodoaryl cyclohexyl ketones as starting materials.
7a
In the presence of Pd(dba)
2
(5 mol%) and CO (41 bar), quinones were pro-
duced in good yields with 100% regioselectivity (Scheme 10.3). Here, the
selection of the catalyst system was important, because 58% of 3a and 3b
were formed instead of quinones if a Pd(OAc)
2
/PPh
3
system was used. This
latter work can be considered as the first real Pd-catalysed intramolecular
carbonylative Heck reaction. In 1996, a full account using different vinyl
iodides was published by the same group.
7b
In 2002, Ryu et al. reported similar reactions which were catalysed by Pd in
the presence of light.
7e
Similar products are obtained by the palladium-
catalysed carbonylative coupling of allyl acetate with benzynes.
7f
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