AuIII-Catalyzed Cycloisomerization of Tertiary Allenyl Carbinols
SHORT COMMUNICATION
activated by protonation of the hydroxy group.[19] Applying
the AgI-catalysts we did not observe these side-products at
all.
Acknowledgments
This work was supported by the Fonds der Chemischen Industrie
and by the AURICAT EU-RTN (HPRN-CT-2002-00174).
We finally tested Gagosz[20] new (Ph3P)AuNTf2 catalyst
as a gold() catalyst for this reaction. Only 3 mol-% of this
catalyst in dichloromethane at room temperature converted
1 to the volatile 2 in an essentially quantitative yield (in situ
1H NMR) and 5 to 6 in 87% isolated yield.
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Similar oxidative dimerizations of a substrate could re-
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[6]
mains: in the individual case, does this reduction convert [7]
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forming a catalytically active species from a precatalyst or
[9]
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Experimental Section
[11]
Reaction of 1 with AuCl3: Compound 1 (250 mg, 1.81 mmol) was
dissolved in absolute acetonitrile (5 mL) under dinitrogen and
AuCl3 (26.5 mg, 87.4 µol) was added. The reaction was monitored
by TLC, after consumption of the starting material the solvent was
removed and the crude material was purified by column
chromatography on silica gel (hexane/ethyl acetate, 40:1) to yield
118 mg (47%) of the known[21] compound 2, 25.4 mg (10%) of the
hitherto unknown 3 and 2.9 mg (1%) of the known[22] compound
4.
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[13] CCDC-292999 (for 3), -293000 (for 6), -293001 (for 7) and -
293002 (for 9) contain the supplementary crystallographic data
for this paper. These data can be obtained free of charge from
The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
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387–391.
3: M.p. 98 °C. R = 0.46 (hexane/ethyl acetate, 10:1). IR (neat): ν
˜
f
= 3069, 2923, 2856, 1742, 1450, 1312, 1091, 931 cm–1. 1H NMR
(250 MHz, CDCl3): δ = 5.66 (t, J = 1.8 Hz, 2 H), 4.74 (d, J =
1.8 Hz, 4 H), 1.70–1.30 (m, 20 H) ppm. 13C NMR (62.9 MHz,
CDCl3): δ = 131.0 (s, 2 C), 130.1 (d, 2 C), 90.3 (s, 2 C), 73.0 (t, 2
C), 36.7 (t, 4 C), 25.1 (t, 2 C), 23.2 (t, 4 C) ppm. MS (70 eV):
m/z (%) = 274 (100) [M+], 203 (43), 231 (87). C18H26O2 (274.4):
calcd. C 78.79, H 9.55; found C 78.57, H 9.67.
4: Rf = 0.78 (hexane/ethyl acetate, 5:1). 1H NMR (250 MHz,
CDCl3): δ = 5.64 (q, J = 1.2 Hz, 1 H), 5.36 (d, J = 1.0 Hz, 1 H),
5.12 (t, J = 1.2 Hz, 1 H), 2.42–2.35 (m, 2 H), 2.20–2.10 (m, 2 H),
1.70–1.40 (m, 6 H) ppm. 13C NMR (62.9 MHz, CDCl3): δ = 146.8
(s), 120.0 (d), 114.2 (t), 77.0 (s), 36.9 (t), 29.5 (t), 28.1 (t), 27.6 (t),
26.3 (t) ppm. MS (70 eV): m/z (%) = 156 (2) [M+], 18 (100), 91 (44),
92 (34).
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[19] It is conceivable that the elimination of water is induced by
AuI, leading to a AuIII intermediate which then leads to 10 by
a ligand exchange with C and a subsequent reductive elimi-
nation.
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Supporting Information (for details see the footnote on the first
page of this article): Procedures and identification data for the
starting materials 1 and 5 and procedure for the gold-catalyzed
reaction that leads to 6–10 including characterization data for these
compounds.
8126.
Received: January 4, 2006
Published Online: January 30, 2006
Eur. J. Org. Chem. 2006, 1387–1389
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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