Palladium/Copper-Catalyzed Di-a-arylation of Acetic Acid Esters
(70 eV): m/z (%)=296 (4) [M+], 195 (100), 180 (27), 165
˜
(25); IR (KBr): n=2977 (m), 1732 (vs), 1508 (s), 1477 (m),
1368 (m), 1277 (m), 1149 (s), 1020 (m), 806 (m), 777 (m),
755 cmÀ1 (s); anal. calcd. for C18H20O2: C 80.56, H 7.51;
found: C 80.77, H 7.20.
Acknowledgements
Scheme 2. Pd-catalyzed arylation of ethyl a-phenylacetate.
We thank Dr. F. Collet for helpful discussions, the DFG
(SFB/TRR 3MET), NanoKat for funding, Umicore AG for
the generous donation of precious metals, and the Bayer Sci-
ence & Education Foundation for a Ph.D fellowship for B.S.
more readily than the first. Even under forcing condi-
tions and using a large excess of aryl bromides, we
never observed more than trace quantities of triary-
lated compounds. This can be explained with the
steric bulk of the corresponding enolates, which ap-
pears to hinder their coordination to the palladium
complex.
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1
solid; yield: 115 mg (86%); mp 658C. H NMR (400 MHz,
CDCl3): d=7.21 (d, J=8.0 Hz, 4H), 7.13 (d, J=8.0 Hz, 4H),
4.95 (s, 1H), 4.21 (q, J=8.0 Hz, 2H), 2.33 (s, 6H), 1.26 (t,
J=8.0 Hz, 3H); 13C NMR (101 MHz, CDCl3): d=172.7,
136.7, 136.0, 129.2, 128.4, 61.0, 56.3, 21.0, 14.1; EI-MS
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Adv. Synth. Catal. 2011, 353, 1688 – 1694
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