LETTER
Synthesis of Functionalized Allylic Alcohols
379
Furthermore, this method may be useful for the synthesis
of different flavonoid derivatives.
X
+
[Pd]
PdX
B
Ha
H
OH
Supporting Information for this article is available online at
Ha
OH
H
Hb
Hb
R
A
R
Acknowledgment
A
E
Financial support by the Department of Science and Technology
[(DST), CHE/2010-11/006/DST/GSN], New Delhi and Indian In-
stitute of Technology (IIT) Hyderabad is gratefully acknowledged.
We thank Dr. S. J. Gharpure for his valuable suggestions. J.K.,
A.G.K., B.V.R., and L.M. thank CSIR, New Delhi, for the award of
research fellowship.
Ha
OH
1
H
Ha
H
OH
3
Hb
3
1
2
H
2
Hb
H
XPd
XPd
R
F
R
G
Hb
References
H
OH
1
Hb
OH
1
H
3
Ha
3
(1) (a) Heck, R. F. J. Am. Chem. Soc. 1968, 90, 5526. (b)Heck,
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345.
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Chem. Rev. 1996, 96, 365.
2
Ha
2
H
H
XPd
XPd
R
R
H
I
HaX
HaX
OH
R
+ [Pd]
D
(3) Melpolder, J. B.; Heck, R. F. J. Org. Chem. 1976, 41, 265.
(4) Chalk, A. J.; Magennis, S. A. J. Org. Chem. 1976, 41, 273.
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T. Tetrahedron Lett. 1990, 31, 6641. (c) Jeffery, T. J. Chem.
Soc., Chem. Commun. 1991, 324.
Scheme 5 Plausible mechanistic path for the formation of b-aryl al-
lylic alcohol D. For simplicity, ligands are omitted.
well could restrict the rotation and therefore afford the al-
lylic alcohol 3 as a major product.
(6) For the relevant topic, see review: Muzart, J. Tetrahedron
2005, 61, 4179.
A possible mechanistic path can be reasoned as shown in
Scheme 5. It appears that the addition of the initially
formed aryl palladium species E to the double bond of the
allylic alcohol A gives both the syn (F) and anti interme-
diates (G) with respect to the hydroxy group. Even though
syn-b-hydride–PdX elimination in the case of intermedi-
ate G seems possible, this process might be restricted due
to the bulky nature of the benzylic alcohol part. In addi-
tion C-1–C-2 bond rotation could be restricted in the right
half of both intermediates F and G, respectively. Now, the
possible rotation of 120° around C-2–C-3 bond of the left
hand part of the intermediates F and G, towards the direc-
tion of minimal eclipsed interaction, leads to the forma-
tion of intermediates H and I, respectively. Finally, syn-b-
hydride–PdX elimination from both H and I yields the
same allylic alcohol as product D (Scheme 1) and com-
pletes the catalytic cycle.
(7) (a) Tamaru, Y.; Yamada, Y.; Yoshida, Z. Tetrahedron 1979,
35, 329. (b) Aslam, M.; Elango, V.; Davenport, K. G.
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Stoudt, C.; Lerner, R. A. J. Am. Chem. Soc. 1993, 115,
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(l) Ferreira, B. R. V.; Pirovani, R. V.; Souza-Filho, L. G.;
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In summary, we have developed a highly regio- and stereo-
selective Pd-catalyzed b-arylation on allylic alcohols
using aryl iodides, 1-bromo-2-iodobenzenes, and 2-bro-
mobenzaldehydes as coupling partners. The observation
was unexpected under conventional Jeffery conditions
without using silver salts as additives. The method is effi-
cient and functioned smoothly on a variety of electron-
rich and electron-deficient aromatic systems and lead to
the products with dense functionality on aromatic rings.
(8) For domino reactions, see: (a) Dyker, G.; Thöne, A.
J. Prakt. Chem. 1993, 341, 138. (b) Dyker, G.; Kadzimirsz,
D.; Henkel, G. Tetrahedron Lett. 2003, 44, 7905.
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Motti, E.; Muzart, J. J. Organomet. Chem. 2003, 687, 473.
(d) Dyker, G.; Grundt, P.; Markwitz, H.; Henkel, G. J. Org.
Chem. 1998, 63, 6043.
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Synlett 2012, 23, 375–380