120
E. Shirakawa, T. Hiyama / Journal of Organometallic Chemistry 653 (2002) 114Á121
/
Scheme 20.
tion 4.1 (Scheme 20, B), (3) b-tin elimination from a 5-
(stannylmethyl)palladacyclopent-2-ene in Section 5.1.
(Scheme 20, C).
These activation methods will provide us with clues to
further investigation concerning not only new carbos-
tannylation reactions of carbonÁcarbon unsaturated
/
bonds using other organostannanes but also tandem
carbostannylation involving two different unsaturated
compounds and carbometalation using other organo-
metallic compounds.
Acknowledgements
We are grateful to our co-workers whose names are
described in the references listed below. We also thank
the Ministry of Education, Science, Sports and Culture,
Japan, for the Grant-in-Aids for COE Research on
Elements Science, No. 12CE2005 and Scientific Re-
search, No.12750758. E.S. thanks the Asahi Glass
Foundation for financial support.
Scheme 19.
unsaturated ketone 30 to a wide variety of conjugated
and unconjugated enones (Scheme 19). Palladium-cata-
lyzed coupling reaction with ethyl p-iodobenzoate gave
coupling product 31. Conjugated (Z)-b-arylenone 32
was obtained by the cross-coupling reaction with the
aryl iodide after base-catalyzed isomerization, whereas
the corresponding (E)-isomer 33 was obtained by
isomerization of unconjugated enone 31. The cross-
coupling reaction with benzoyl chloride gave enedione
34, and 30 reacted with iodomethane in the presence of
sodium hydride, giving dimethylated product 35, which
was subjected to the cross-coupling reaction with the
aryl iodide to afford aryl-substituted b,g-enone 36.
References
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(b) H. Yoshida, E. Shirakawa, T. Kurahashi, Y. Nakao, T.
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8. Conclusion and prospect
[3] E. Shirakawa, K. Yamasaki, H. Yoshida, T. Hiyama, J. Am.
Chem. Soc. 121 (1999) 10221.
The transition metal-catalyzed carbostannylation re-
action disclosed here, in addition to the carbostannyla-
tion of 1,3-dienes [11] and arynes [12], is based on a
[4] We have already given an account on how we found the
alkynylstannylation of alkynes. E. Shirakawa, T. Hiyama, J.
Organomet. Chem. 576 (1999) 169.
[5] E. Shirakawa, H. Yoshida, T. Hiyama, Tetrahedron Lett. 38
(1997) 5177.
variety of activation methods of a carbonÁ
organostannanes by transition metals, (1) oxidative
addition of a carbonÁtin bonds to a palladium(0) or
/
tin bond of
[6] E. Shirakawa, Y. Nakao, T. Tsuchimoto, T. Hiyama, submitted
for publication.
/
nickel(0) complex (Scheme 20, A), (2) the reaction of a
palladacyclopentadiene with an organostannane in Sec-
[7] (a) E. Shirakawa, H. Yoshida, Y. Nakao, T. Hiyama, J. Am.
Chem. Soc. 121 (1999) 4290;