Palladium-Catalyzed Decarboxylative Acylation of O-Phenyl Carbamates
with EtOAc (10 mL ꢁ 3). The combined organic layer was
dried over Mg2SO4 and concentrated under vacuum. The
residue was purified by silica gel column chromatography
(n-hexanes/EtOAc=10:1) to afford 3; yield: 60.2 mg (66%).
Acknowledgements
This work was supported by National Research Foundation
of Korea (No. 2010-0002465) funded by the Ministry of Edu-
cation, Science and Technology.
References
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Scheme 3. Postulated mechanism.
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product 3a, and regenerate Pd(0) catalyst. Finally,
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(NH)4S2O8. Although the alternative mechanistic
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catalytic cycles are reasonable to consider, we favor
(II/III)[24] and/or Pd(II/IV)[25]
ACHUTGTNRENNUG CAHTUNGTRENNUGN
the reaction mechanism based on the Pd
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À
via C H bond activation. Our ongoing works seek to
2
À
expand the scope to the acylation of sp C H bonds
without directing groups and unactivated sp3 C H
bonds.
À
Experimental Section
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Typical Procedure for the Acylation of O-Phenyl
Carbamates
To an oven-dried sealed tube charged with 4-chlorophenyl
dimethylcarbamate (1d) (59.9, 0.3 mmol, 1.0 equiv.),
879.
2
À
[11] For a recent review on catalytic acylation of sp C H
Pd
N
bonds, see: C. Pan, X. Jia, J. Cheng, Synthesis 2012, 44,
677.
(102.6 mg, 0.45 mmol, 1.5 equiv.), and phenylglyoxylic acid
(2a) (90.6 mg, 0.6 mmol, 2 equiv.) in DCE (2 mL) was added
TfOH (5 mL, 20 mol%). The reaction mixture was allowed
to stir at room temperature for 20 h. Then the reaction mix-
ture was diluted with EtOAc (5 mL) and washed with a satu-
rated solution of Na2CO3. The aqueous layer was extracted
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Adv. Synth. Catal. 2013, 355, 667 – 672
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