that the reaction proceeds via two plausible pathways. Further
studies including mechanism details are being taken actively in
this laboratory.
Experimental
General Information. Fe(NO3)3·9H2O was purchased from Energy
Chemical. Liquid aldehydes were distilled before use. MeCN was
refluxed over CaH2 and distilled right before use. Petroleum ether
(60-90 oC) was used for chromatography. Other reagents were
used as received without further treatment. Substrate 1b, 1e, 1f,
1l, 1m, and 1n were synthesized via iron-catalyzed aerobic
oxidation of corresponding alcohols.13
Caution: Oxygen in use in combination with organic solvents;
remove all ignition sources including sources of sparks, static, or
flames since oxygen increases intensity of any fire. Inhalation of
pure oxygen should be avoided as well.
Supporting Information
The supporting information for this article is available on the
Synthesis of dodecanoic acid (2a)(Table 3, entry 1): to a Schlenk
tube were added Fe(NO3)3·9H2O (20.1 mg, 0.05 mmol), 1a (184.1
mg, 1.0 mmol), and MeCN (4 mL) sequentially under the
atmosphere of oxygen from a gas bag (commercial size: 2 L, could
be expended to 5 L). The Schlenk tube was then stirred at 25 oC
until completion of the reaction as monitored by TLC (petroleum
ether/ ethyl acetate = 5/1) (12 h). The crude reaction mixture was
filtrated through a short column of silica gel (height: 2 cm, Φ: 3
cm) eluted with diethyl ether (25 × 3 mL). After evaporation, the
residue was purified by chromatography on silica gel to afford 2a
(164.4 mg, 82%) (eluent: petroleum ether/ethyl acetate = 5/1) as
Acknowledgement
Financial support from National Basic Research Program
(2015CB856600) is greatly appreciated. We thank Dr.
Minqiang Jia and Dr. Tao Cao in this group for reproducing
the results of 2f and 2h in Table 3 and 2c in Scheme 2.
solid: m.p. 43.1-44.0 oC (petroleum ether/ethyl acetate)
References
a
(reported:14 43-44 °C); 1H NMR (400 MHz, CDCl3) δ 11.79 (brs, 1 H,
COOH), 2.35 (t, J = 7.6 Hz, 2 H, CH2), 1.69-1.56 (m, 2 H, CH2),
1.40-1.18 (m, 16 H, 8 × CH2), 0.88 (t, J = 6.2 Hz, 3 H, CH3); 13C NMR
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24.6, 22.7, 14.1, IR (neat, cm-1): 3400-2300, 1695, 1468, 1429,
1410, 1301, 1277, 1248, 1219, 1193; MS (EI, 70 eV) m/z (%): 200
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