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Synlett 2011(16): 2407-2409  
DOI: 10.1055/s-0030-1261224
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Copper-Catalyzed Domino Oxidation-Acyloxylation Reaction of 2-Arylpyridines with Aldehydes or Methylarenes

Yong-Jun Biana, Chang-Bing Xianga, Zhi-Ming Chena, Zhi-Zhen Huang*a-c
a School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. of China
Fax: +86(25)83686231.; e-Mail: huangzz@nju.edu.cn;
b Department of Chemistry, Zhejiang University, Hangzhou 310028, P. R. of China
c State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin 300071, P. R. of China
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Publikationsverlauf

Received 4 June 2011
Publikationsdatum:
08. September 2011 (online)

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Abstract

A domino oxidation-acyloxylation reaction of 2-aryl­pyridines with aldehydes or methylarenes under the catalysis of Cu(OAc)2 has been developed. The strategy via C-H bond functionalization has the advantages of good functional-group tolerance, high ortho regioselectivity and no need of any ligand or additive.

Key words

C-H activation - copper catalysis - domino reaction - acyloxylation - oxidation

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General Procedure for the Oxidation-Acyloxylation Reaction of 2-Arylpyridine 1 with Aldehydes 2
To a mixture of 2-arylpyridine (0.25 mmol), aldehyde (0.5 mmol), Cu(OAc)2 (10 mol%, 4.5 mg), and chlorobenzene (2 mL) was added tert-butyl hydroperoxide (2 equiv, 5.5 M in decane) dropwise at r.t. The reaction mixture was stirred at 135 ˚C for 24 h. After the reaction, EtOAc (10 mL) was added, and the mixture was washed with aq NaOH (1 M, 5 mL), H2O (10 mL), and brine (10 mL), respectively. The filtrate was dried over Na2SO4 and then concentrated in vacuo. The residue was purified by column chromatography (silica gel, PE-EtOAc as eluent) to afford the desired products 3a-n.

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Unexpectedly, when toluene was employed under the optimal conditions, only a trace amount of benzoxylated product was obtained.