Chin. J. Org. Chem. ›› 2019, Vol. 39 ›› Issue (1): 265-269.DOI: 10.6023/cjoc201806024 Previous Articles     Next Articles

Articles

氧化锌促进的醛与[Ph3P+CF2H·Br-]的Wittig偕二氟烯基化反应

于蛟, 林锦鸿, 肖吉昌   

  1. 中国科学院上海有机化学研究所 有机氟化学重点实验室 中国科学院大学 上海 200032
  • 收稿日期:2018-06-15 修回日期:2018-07-06 出版日期:2019-01-25 发布日期:2018-07-24
  • 通讯作者: 肖吉昌 E-mail:jchxiao@sioc.ac.cn
  • 基金资助:

    国家重点基础研究发展计划(973计划,No.2015CB931903)、国家自然科学基金(Nos.21421002,21472222,21502214,21672242)、中国科学院(Nos.XDA02020105,XDA02020106)、中国科学院前沿科学重点研究计划(No.QYZDJSSW-SLH049)资助项目.

ZnO-Promoted Wittig gem-Difluoroolefination of Aldehydes with [Ph3P+CF2H·Br-]

Yu Jiao, Lin Jinhong, Xiao Jichang   

  1. Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032
  • Received:2018-06-15 Revised:2018-07-06 Online:2019-01-25 Published:2018-07-24
  • Contact: 10.6023/cjoc2018006024 E-mail:jchxiao@sioc.ac.cn
  • Supported by:

    Project supported by the National Basic Research Program of China (973 Program, No. 2015CB931903), the National Natural Science Foundation of China (Nos. 21421002, 21472222, 21502214, 21672242), the Chinese Academy of Sciences (Nos. XDA02020105, XDA02020106), and the Key Research Program of Frontier Sciences (CAS) (No. QYZDJSSW-SLH049).

Wittig gem-difluoroolefination of aldehydes with difluoromethyl phosphonium salt (Ph3P+CF2H·Br-) by using zinc oxide as a base is described. Although the proton in the CF2H group is acidic and a base could easily lead to its deprotonation to form ylide (Ph3P+CF2-), the attack of the base at the positive phosphorus atom may also take place to produce a nucleophilic [HCF2-] equivalent, and then nucleophilic difluoromethylation instead of Wittig reaction would occur. The use of ZnO as the base favored the Wittig reaction and the nucleophilic difluoromethylation was not observed. Furthermore, the excessive ZnO and Zn salts produced from ZnO could be easily removed by filtration, which may be convenient for the purification process.

Key words: Wittig, gem-difluoroolefination, aldehydes, difluoromethyl phosphonium salt, zinc oxide