Angewandte
Chemie
(278 mg, 1 mmol) was added to the resulting slurry (slow addition
during 6 h) with stirring at 958C in an oxygen atmosphere. The
reaction mixture was cooled down to room temperature after a
further 2 h, and 2m NaOH (10 mL) was added. The resulting mixture
was extracted with Et2O (3 5 mL), the combined organic phases
were dried (Na2SO4), and the solvent was removed under vacuum to
yield 265 mg (96%) of pure product 2a. Purification of 2, when
needed, was carried out by using Biotage SP1 flash chromatography
with eluent system pentane/ethyl acetate (10:1).
Lett. 2005, 7, 5717; d) E. M. Beck, N. P. Grimster, R. Hatley, M. J.
Gaunt, J. Am. Chem. Soc. 2006, 128, 2528.
[14] C. Adamo, C. Amatore, I. Ciofini, A. Jutand, H. Lakmini, J. Am.
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À
[16] For a recent interesting anaerobic oxidation with C C bond
formation through an outer-sphere nucleophilic attack of indole
on an (olefin)palladium complex, see: C. Liu, R. A. Widenhoe-
fer, Chem. Eur. J. 2006, 12, 2371.
[17] J. Franzꢂn, J.-E. Bäckvall, J. Am. Chem. Soc. 2003, 125,
6056.
Received: June 15, 2006
Revised: August 9, 2005
[18] K. Närhi, J. Franzꢂn, J.-E. Bäckvall, Chem. Eur. J. 2005, 11,
6937.
Published online: September 26, 2006
[19] The acyclic starting materials 1g–h were obtained in the same
way as the cyclic starting materials 1a–e from the corresponding
acyclic allylic acetates.
[20] For more information on the thermal ene reaction, see: K. Närhi,
J. Franzꢂn, J.-E. Bäckvall, J. Org. Chem. 2006, 71, 2914.
[21] With 1a and Pd(O2CCF3)2 (5 mol%) in toluene at 958C in an O2
atmosphere, a mixture of 2a, 6, 7, and additional unidentified by-
products were formed; unfortunately the ratio between 2a, 6,
and 7 could not be determined.
[22] A similar isomerization occurs in the palladium(0)-catalyzed
cycloisomerization reaction of enallenes. See Ref. [18].
[23] The FePc was attached to a polystyrene resin (aminomethylated
polystyrene (50–100 mesh)) through a sulfonamide group; for
reviews on solid-phase reactions, see: a) B. A. Lorsbach, M.
Kurth, Chem. Rev. 1999, 99, 1549; b) R. E. Sammelson, M.
Kurth, Chem. Rev. 2001, 101, 137.
[24] These results are consistent with the rate-determining step being
the reoxidation of the hydroquinone to its corresponding
quinone.
Keywords: aerobic oxidation · allenes · allylic oxidation ·
homogeneous catalysis · palladium
.
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Angew. Chem. Int. Ed. 2006, 45, 6914 –6917ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
6917