Acta Chim. Sinica ›› 2017, Vol. 75 ›› Issue (1): 60-65.DOI: 10.6023/A16070375 Previous Articles     Next Articles

Special Issue: 有机光化学



周能能a, 胥攀a, 李伟鹏a, 成义祥a, 朱成建a,b   

  1. a 南京大学化学化工学院 配位化学国家重点实验室 南京 210093;
    b 中国科学院上海有机化学研究所 金属有机化学国家重点实验室 上海 200032
  • 投稿日期:2016-07-30 修回日期:2016-09-13 发布日期:2016-09-18
  • 通讯作者: 朱成建,;Tel.:025-83686219
  • 基金资助:


Visible Light Promoted Carbodifluoroalkylation of Homopropargylic Alcohols via Concomitant 1,4-Aryl Migration

Zhou Nengnenga, Xu Pana, Li Weipenga, Cheng Yixianga, Zhu Chengjiana,b   

  1. a State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093;
    b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Shanghai 200032
  • Received:2016-07-30 Revised:2016-09-13 Published:2016-09-18
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21172106, 21174061, 21474048 and 21372114).

Fluorinated compounds have gained much attention because of their unique electronegativity, metabolic stability and bioavailability, and thus, the synthesis of organofluorine compounds has found wide applications in pharmaceuticals, agrochemicals, and materials science. Among them, the incorporation of a difluoromethyl group (CF2) into organic compounds is of great concern in medicinal chemistry owing to its isosterism with the hydroxyl group. Therefore, the development of new difluoroalkylation methods has attracted great interest in synthetic organic chemistry. Visible light-driven photocatalysis as an eco-friendly and powerful theme has been widely utilized in organic synthesis. In particular, free radical fluorination is emerging as a powerful tool for C-F bond formation, especially under the catalysis of visible light. Recent progress on the visible light-promoted directing difluoroalkylation using ethyl bromodifluoroacetate provided an efficient approach to the target. Herein, we report a contribution towards visible light induced carbodifluoroalkylation of homopropargylic alcohols with the use of ethyl bromodifluoroacetate as a source of difluorinated moieties. This strategy provides a facile way to access functional-difluorinated alkenes through a tandem radical difluoroalkylation and 1,4-aryl migration process. A representative procedure for this reaction is as following:An oven-dried Schlenk tube (10 mL) was equipped with a magnetic stir bar, homopropargylic alcohols (0.2 mmol), fac-Ir(ppy)3 (0.02 equiv., 0.004 mmol), 2-bromo-2,2-difluoroacetate (2.5 equiv. 0.5 mmol), Na2HPO4 (2 equiv., 0.4 mmol). The flask was evacuated and backfilled with Ar for 3 times. 0.5 mL of dry DMA and 0.5 mL of dry DCE were added with syringe under Ar. The tube was placed at a distance (app. 5 cm) from 33 W fluorescent light bulb, and the resulting solution was stirred at ambient temperature under visible-light irradiation. After the reaction was finished, the mixture was then diluted with MTBE (20 mL×2) and water. The combined organic layers were dried over sodium sulfate and the solvent concentrated in vacuo and the residue was purified by chromatography on silica gel to afford the corresponding products.

Key words: carbodifluoroalkylation, homopropargylic alcohols, 1,4-aryl migration, photoredox catalytic reaction