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LETTER
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(14) General Procedure: An 50-mL vial was charged with
magnetic stir bar, pyridine N-oxide (1a; 1.5 mmol), benzyl
chloride (2a; 1.0 mmol), Pd(OAc)2 (0.05 mmol), t-Bu3P–
HBF4 (0.1 mmol), K2CO3 (2.0 mmol), followed by anhyd
toluene (3 mL). After stirring at 110 °C for 16 h, the reaction
mixture was filtered through Celite (washed with MeOH and
CH2Cl2). The combined organic phase was then evaporated
under reduced pressure and the isolated yield was obtained
by flash chromatography column on silica gel (gradient
eluent of MeOH in CH2Cl2: 1–5%).
2-Benzylpyridine N-Oxide (3aa): yellow solid. 1H NMR
(400 MHz, CDCl3): d = 8.32 (d, J = 2.8 Hz, 1 H), 7.33–7.40
(m, 2 H), 7.28–7.31 (m, 3 H), 6.95–7.19 (m, 2 H), 6.93–6.95
(m, 1 H), 4.28 (s, 2 H). 13C NMR (100 MHz, CDCl3): d =
151.9, 139.4, 136.2, 129.7, 128.8, 127.1, 125.8, 125.6,
123.6, 36.5. MS (ESI): m/z = 186.0 [M + 1]+. HRMS (ESI):
m/z [M + H]+ calcd for C12H12NO+: 186.0919; found:
186.0913.
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K. H.; Zaharevitz, D.; Gussio, R.; Giannakakou, P. Chem.
Biol. 2000, 7, 593. (c) Quiroga, J.; Trilleras, J.; Insuasty, B.;
Abonia, R.; Nogueras, M.; Marchal, A.; Cobo, J.
2-(2-Methylbenzyl)pyridine N-Oxide (3ab): 1H NMR
(400 MHz, CDCl3): d = 8.32 (d, J = 6.4 Hz, 1 H), 7.10–7.27
(m, 6 H), 6.71 (d, J = 7.2 Hz, 1 H), 4.25 (s, 2 H), 2.19 (s, 3
H). 13C NMR (100 MHz, CDCl3): d = 151.3, 139.4, 137.2,
134.4, 130.6, 127.5, 126.5, 125.7, 125.9, 125.1, 123.4, 34.4,
19.3. HRMS (ESI): m/z [M + H]+ calcd for C13H14NO+:
200.1075; found: 200.1073.
2-(4-Fluorobenzyl)pyridine N-Oxide (3ac): pale yellow
solid. 1H NMR (400 MHz, CDCl3): d = 8.35 (d, J = 5.2 Hz,
1 H), 7.19–7.28 (m, 4 H), 6.99–7.07 (m, 3 H), 4.26 (s, 2 H).
13C NMR (100 MHz, CDCl3): d = 163.2, 160.7, 151.6, 149.5,
131.9, 131.2, 125.7, 123.7, 123.9, 115.8, 35.8. HRMS (ESI):
m/z [M+H]+ calcd for C12H11FNO+: 204.0825; found:
204.0827.
Tetrahedron Lett. 2010, 51, 1107. (d) Nolan, E. M.;
Jaworski, J.; Okamoto, K. I.; Hayashi, Y.; Sheng, M.;
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G. D.; Hoemann, M. Z.; Hauske, J. R.; Chopra, I.
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P. N. W.; Lehn, J. M.; Fischer, J.; Youinou, M. T. Angew.
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2-(3-Trifluoromethylbenzyl)pyridine N-Oxide (3ad): 1H
NMR (400 MHz, CDCl3): d = 8.28–8.30 (m, 1 H), 7.44–7.55
(m, 4 H), 7.18–7.21 (m, 2 H), 7.00–7.03 (m, 1 H), 4.32 (s, 2
H). 13C NMR (100 MHz, CDCl3): d = 150.8, 139.6, 137.3,
137.1, 133.0, 131.2, 130.9, 128.6, 129.3, 126.2, 126.17,
126.13, 126.1, 125.9, 125.7, 125.4, 124.1, 123.99, 123.95,
123.91, 122.66, 36.4. HRMS (ESI): m/z [M + H]+ calcd for
C13H11F3NO+: 254.0793; found: 254.0796.
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J. Am. Chem. Soc. 2010, 132, 14391.
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Synlett 2012, 23, 938–942
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