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LETTER
OH
R2
References and Notes
R1
(1) Mallat, T.; Baiker, A. Chem. Rev. 2004, 104, 3037.
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(
2
+
N
2
O
(
4) Cainelli, G.; Cardillo, G. Chromium Oxidations in Organic
Chemistry; Springer: Berlin, 1984.
O
Au(III)
(5) Trahanovsky, W. S. Oxidation in Organic Chemistry;
Blomquist, A. T.; Wasserman, H., Eds.; Academic Press:
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(6) Mori, K.; Yamaguchi, K.; Hara, T.; Mizugaki, T.; Ebitani,
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R1
R2
+
N
OH
(
(
7) Uozumi, Y.; Nakao, R. Angew. Chem. Int. Ed. 2003, 42, 194.
8) Yamaguchi, K.; Mizuno, N. Angew. Chem. Int. Ed. 2002, 41,
1/4 O2
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538.
(
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J. Am. Chem. Soc. 2004, 126, 1065.
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11) Lenz, R.; Ley, S. V. J. Chem. Soc., Perkin Trans. 1 1997,
Scheme 2 The mechanism of oxidation of alcohols
(
(
(
3
291.
General Procedure for the Preparation of Imim-PEG1000-TEMPO
To a solution of PEG-1000 (0.06 mol, 60 g) in toluene (150 mL)
pyridine (0.12 mol, 9.6 mL) was added, followed by SOCl (0.12
12) Marko, I. E.; Giles, P. R.; Tsukazaki, M.; Chelle-Regnaut, I.;
Urch, C. J.; Brown, S. M. J. Am. Chem. Soc. 1997, 119,
2
1
2661.
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002, 3034.
mol, 8.7 mL) over 30 min under N atmosphere at 0 °C. The result-
2
(
(
ing slurry was stirred for 24 h at r.t. and filtered. Toluene was then
removed by rotary evaporation under reduced pressure to give inter-
mediate 1 as a gray viscous liquid. To a suspension of Na (1.15 g,
2
14) Zhan, B. Z.; White, M. A.; Sham, T. K.; Pincock, J. A.;
Doucet, R. J.; Rao, K. V. R.; Robertson, K. N.; Cameron,
T. S. J. Am. Chem. Soc. 2003, 125, 2195.
0.05 mol) in benzene (100 mL) 4-hydroxy-TEMPO (8.6 g, 0.05
mol) was added, and the resulting slurry was stirred for 8 h at r.t. un-
der reflux. Intermediate 1 (0.025 mol) was then added and stirring
resumed for 12 h at r.t. The suspension was then filtered, and the fil-
trate was concentrated under reduced pressure. This solution was
(
15) Ji, H. B.; Mizugaki, T.; Ebitani, K.; Kaneda, K. Tetrahedron
Lett. 2002, 43, 7179.
(16) Semmelhack, M. F.; Schmid, C. R.; Cortés, D. A.; Chou,
C. S. J. Am. Chem. Soc. 1984, 106, 3374.
then added to Et O, the mixture stirred vigorously, the precipitate
2
collected by filtration, washed twice with Et O (50 mL), and dried
(17) Skibida, I. P.; Sakharov, A. M. Catal. Today 1996, 27, 187.
(18) Markó, I. E.; Giles, P. R.; Tsukazaki, M.; Chellé-Regnaut, I.;
Gautier, A.; Brown, S. M.; Urch, C. J. J. Org. Chem. 1999,
64, 2433.
(19) Markó, I. E.; Giles, P. R.; Tsukazaki, M.; Brown, S. M.;
Urch, C. J. Science 1996, 274, 2044.
2
under vacuum. The product 2 was obtained as orange-red viscous
solid. To N-methylimidazole (2.05 g, 0.025 mol) dissolved in tolu-
ene, intermediate 2 (0.025 mol) was added, and the mixture was
stirred at 80 °C for 20 h. The reaction progress was determined by
HPLC and, when complete, the mixture was evaporated under re-
duced pressure to give Imim-PEG1000-TEMPO as an orange red
oil with a yield of 98.%.
(20) Wang, Y.; DuBois, J. L.; Hedman, B.; Hodgson, K. O.;
Stack, T. D. P. Science 1998, 279, 537.
(
21) Chaudhuri, P.; Hess, M.; Flörke, U.; Wieghardt, K. Angew.
Chem. Int. Ed. 1998, 37, 2217.
General Procedure for the Oxidation of Alcohols
To a 10 mL round-bottom flask, Imim-PEG1000-TEMPO (0.5
(22) Ragagnin, G.; Betzemeier, B.; Quici, S.; Knochel, P.
Tetrahedron 2002, 58, 3985.
mmol), AuCl (0.5 mmol) and benzyl alcohol (10 mmol) were suc-
3
cessively added with vigorous stiring. The reaction was allowed to
proceed at 60 °C and monitored by TLC. Upon completion, the re-
action mixture was cooled to r.t. and extracted three times by adding
Et O. The organic phase was dried over anhydrous MgSO , filtered,
(
(
23) Ansari, I. A.; Gree, R. Org. Lett. 2002, 4, 1507.
24) Liu, L.; Ji, L. Y.; Wei, Y. Y. Monatsh. Chem. 2008, 139,
9
01.
25) Wu, X. E.; Ma, L.; Ding, M. X.; Gao, L. X. Synlett 2005,
07.
2
4
(
(
(
and evaporated under reduced pressure to give benzaldehyde (95%
yield). All products had spectroscopic data consistent with the as-
signed structures.
6
26) Abad, A.; Concepción, C.; Corma, A.; García, H. Angew.
Chem. 2005, 117, 4134.
27) Enache, D. I.; Edwards, J. K.; Landon, P.; Solsona-Espriu,
B.; Carley, A. F.; Herzing, A. A.; Watanabe, M.; Kiely, C.
J.; Knight, D. W.; Hutchings, G. J. Science 2006, 311, 362.
28) Miyamura, H.; Matsubara, R.; Miyazaki, Y.; Kobayashi, S.
Angew. Chem. Int. Ed. 2007, 119, 4229.
Acknowledgment
This work was supported financially by the Natural Science Foun-
dation (No. 11076017).
(
(
29) Yuan, Y.; Bian, Y. B. Tetrahedron Lett. 2007, 48, 8518.
Synlett 2014, 25, 2459–2462
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