ORGANIC
LETTERS
2011
Vol. 13, No. 21
5932–5935
Palladium(II)-Catalyzed Dehydrogenative
Alkenylation of Cyclic Enaminones via the
FujiwaraÀMoritani Reaction
Yi-Yun Yu, Micah J. Niphakis, and Gunda I. Georg*
Department of Chemistry and Department of Medicinal Chemistry and the Institute for
Therapeutics Discovery and Development, University of Minnesota, 717 Delaware Street
SE, Minneapolis, Minnesota 55414, United States
Received October 5, 2011
ABSTRACT
A new Pd(II)-catalyzed dehydrogenative alkenylation reaction involving two alkenes was developed. A variety of nonaromatic, cyclic enaminones
were successfully coupled to primary and secondary alkenes yielding a series of unique 1,3-dienes. The generality of this transformation presents
a useful strategy for directly cross-coupling alkenes and offers an attractive new approach to functionalize enaminones.
Direct CÀH functionalization chemistry has seen sig-
nificant progress during the past decade.1 Cross dehydro-
genative coupling reactions that use two CÀH bonds to
form a new CÀC bond are highly sought after, because
these processes do not require prefuntionalization and as a
result have high atom economy.2 The FujiwaraÀMoritani
reaction is a process by which aromatic substrates undergo
an intermolecular dehydrogenative alkenylation. This
reaction was initially developed using stoichiometric amounts
of Pd(II) (Figure 1a)3 but soon thereafter was shown to
also take place with catalytic amounts of Pd(II) (Figure 1b).4
In recent years, the scope of the FujiwaraÀMoritani has
been expanded to a plethora of aromatic substrates.5
However, only a few cases of alkenylation reactions invol-
ving two alkene CÀH donors (Figure 1c) are known. They
(5) For recent examples: (a) Le Bras, J.; Muzart, J. Chem. Rev. 2011,
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X. L.; Min, Q. Q.; Yang, J.; Jiang, Z. X. J. Am. Chem. Soc. 2010, 132,
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G. P.; Fairlamb, I. J. S. Eur. J. Org. Chem. 2009, 4011. (e) Kulkarni,
A. A.; Daugulis, O. Synthesis 2009, 4087. (f) Daugulis, O.; Do, H. Q.;
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(3) Moritani, I.; Fujiwara, Y. Tetrahedron Lett. 1967, 1119.
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r
10.1021/ol202677g
Published on Web 10/13/2011
2011 American Chemical Society