Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (10): 805-810.DOI: 10.6023/A16060316 Previous Articles     Next Articles

Article

水相钯(II)催化羰基β位C(sp3)-H芳基化反应 2017 Awarded

罗飞华a,b, 龙洋a, 李正凯a, 周向葛a   

  1. a 四川大学化学学院 成都 610064;
    b 四川文理学院化学与化工学院 达州 635000
  • 收稿日期:2016-07-11 出版日期:2016-10-15 发布日期:2016-09-06
  • 通讯作者: 周向葛,E-mail:zhouxiangge@scu.edu.cn;Tel.:028-85412026;Fax:028-85412904 E-mail:zhouxiangge@scu.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21272161,21472128,J1310008)资助.

Palladium Catalyzed Arylation of C(sp3)-H Bonds of Carbonyl β-position in Water

Luo Feihuaa,b, Long Yanga, Li Zhengkaia, Zhou Xianggea   

  1. a College of Chemistry, Sichuan University, Chengdu 610064, China;
    b Department of Chemistry and Chemical Engineering, Sichuan University of Arts and Science, Dazhou 635000, China
  • Received:2016-07-11 Online:2016-10-15 Published:2016-09-06
  • Supported by:

    Project supported by the National Natural Science Foundation of China (grant Nos. 21272161, 21472128, J1310008).

The direct activation and functionalization of C-H bonds is fundamentally important in organic synthesis. Among different methods developed, transition metal-catalyzed intermolecular arylation of alkanes, which couples unactivated C(sp3)-H bonds with aryl moieties, is recognized as one of the most powerful strategies to construct valuable arylated alkyl scaffolds. Tremendous progress has thus been made in this field, which usually require harsh reaction conditions such as high temperature and inert atmosphere as well as additives. Furthermore, the reaction media were usually organic solvents with undesirable toxicity and volatility, such as toluene, xylene, tert-amyl alcohol, dichloroethane, etc. Therefore, the development of efficient catalytic unactivated C(sp3)-H arylation under mild reaction conditions is still highly demanded. Herein, we reported a general and practical palladium-catalyzed arylation of β-methylene C(sp3)-H under aqueous conditions by the use of 8-aminoquinoline as directing groups. This method exhibited good to excellent yields up to 96% and good functional group tolerance without other additives and inert gas atmosphere. Meanwhile, the reaction showed good regioselectivity to the β-position of carbonyl group. Mechanism studies showed that the aliphatic Ag-carboxylate salt was critical for this reaction. The silver ion might weaken the C-I bond and function as halogen scavenger for the transformation, while pivalic acid ion might act as base during reaction. A representative procedure for this reaction is as following: To a 10 mL glass tube, N-(quinolin-8-yl) butyramide (42.8 mg, 0.2 mmol), iodobenzene (67 μL, 0.4 mmol), Pd(OAc)2 (4.5 mg), AgPiv (83.6 mg, 0.4 mmol) in 0.4 mL H2O were stirred at 60℃ for 24 h, and then cooled to room temperature. The reaction mixture was extracted with EtOAc. The organic phase was washed with water, dried over magnesium sulfate, and concentrated. The crude product was purified with column chromatography (petroleum/EtOAc) to provide the products in 61%~96% yields.

Key words: aqueous, palladium catalysis, 8-aminoquinoline, C-H activation, arylation