Y. Wu et al. / Journal of Organometallic Chemistry 637–639 (2001) 793–795
795
zene with styrene than catalyst 1, probably due to
catalyst 2 being more soluble than catalyst 1. The
coupling reactions of iodobenzene with acrylamide gave
moderate to good yields of trans-cinnamamide.
It is noteworthy that all of these reactions studied
showed high regioseletivity for trans-coupling, and no
cis-product was found.
Besides, the figure of 7.36 million turnovers was
obtained by reducing the amount of catalyst 2 to
1×10−8 mol and prolonging the reaction time to 338 h
in the case of arylation of iodobenzene with butyl
acrylate. The experiment indicated that there were no
changes in the catalytic activity during the repeated
uses of catalyst 2 in the arylation of iodobenzene with
ethyl acrylate for five times. In the case of arylation of
bromobenzene or substituted bromobenzene with ethyl
acrylate by using catalyst 2, moderate to 100% yields
and hundreds to 2.34 million turnovers (in the case of
p-NO2PhBr used as substrate) were obtained. By using
catalyst 2, arylation of p-NO2PhCl with ethyl acrylate
in DMF, 140 °C for 10 h, 73% yield (TON 400) was
obtained.
Catalyst 1 [{[Pd(h5-C5H5)Fe(h5-C5H3)C(CH3)ꢁN(C6-
H4CH3-4)](m-Cl)}2] was a red crystal, yield 92.4%, m.p.
(dec.) \210 °C. IR (cm−1): 3090, 2920, 1551, 1508,
1
1474, 1105, 999, 817, 721, 693. H-NMR (DMSO-d6):
2.01 (s, 6H, CH3), 2.31 (s, 6H, CH3), 4.38 (s, 10H,
C5H5), 4.48 (bs, 2H, H-4), 4.73 (bs, 2H, H-5), 5.14 (bs,
2H, H-3), 6.94 (d, J=6.8 Hz, 4H, C6H4), 7.14 (d, J=8
Hz, 4H, C6H4). Anal. Found: C, 49.92; H, 3.91; N,
2.93. Calc. for C38H36N2Cl2Fe2Pd2: C, 49.82; H, 3.96;
N, 3.06%.
Catalyst 2 [{[Pd(h5-C5H5)Fe(h5-C5H3)C(CH3)ꢁN(C6-
H4CH3-4)](m-I)}2] was an orange red crystal, yield
86.9%, m.p. (dec.) \230 °C. IR (cm−1): 3088, 2918,
1
1562, 1508, 1474, 1106, 1000, 817, 722, 663. H-NMR
(DMSO-d6): 2.01 (s, 6H, CH3), 2.32 (s, 6H, CH3), 4.34
(s, 10H, C5H5), 4.37 (bs, 2H, H-4), 4.62 (bs, 2H, H-5),
5.02 (bs, 2H, H-3), 6.94 (d, J=8 Hz, 4H, C6H4), 7.22
(d, J=8 Hz, 4H, C6H4). Anal. Found: C, 41.59; H,
3.43; N, 2.62. Calc. for C38H36N2I2Fe2Pd2: C, 41.53; H,
3.30; N, 2.55%.
In summary, the cyclopalladated ferrocenylimines
showed exceedingly high catalytic activities and yields
in olefination of iodobenzene, unactivated aryl bro-
mides or chlorides. The high activities in the olefination
of iodobenzene were observed in mild reaction condi-
tions without any additive. Further study on the reac-
tion mechanism is in progress.
Acknowledgements
We are grateful to the National Natural Science
Foundation of China (Projects 29572066, 20072034)
and the Natural Science Foundation of Henan Province
for the financial support given to this research.
References
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