Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (9): 938-944.DOI: 10.6023/A20060268 Previous Articles     Next Articles



杜重阳, 陈耀峰   

  1. 中国科学院 中国科学院大学 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:2020-06-24 发布日期:2020-08-11
  • 通讯作者: 陈耀峰
  • 基金资助:

ZnEt2 Promoted Hydrosilylation of CO2 and Formylation or Urealation of Amines with CO2 as a C1 Building Block

Du Chongyang, Chen Yaofeng   

  1. State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
  • Received:2020-06-24 Published:2020-08-11
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 21821002) and the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB20000000).

Fixation and transformation of CO2 are of the great importance, especially the conversion of CO2 into valuable organic compounds catalyzed by the cheap and biocompatible metal catalysts. Zinc is an abundant, biocompatible and environmentally friendly element. ZnEt2 is commercial available, and has been widely used as reducing or transmetalation agent in hydrocarboxylation of unsaturated hydrocarbons with CO2. In these reactions, ZnEt2 is generally used in stoichiometric amount or excess amout. This manuscript reports the hydrosilylation of CO2 into methoxysilane promoted by a catalytic amount of ZnEt2 (1.0 mol%), the ZnEt2 promoted formylation or urealation of amines with CO2 as a one-carbon (C1) building block is also described. The hydrosilylation of CO2 into methoxysilane (CH3OSi(OEt)3) with (EtO)3SiH as a hydrosilylation reagent is affected by CO2 pressure, ZnEt2 amount, reaction temperature and reaction time. Under the reaction conditions of 1.0 MPa CO2 (the initial CO2 pressure) and 1.0 mol% ZnEt2, the yield of methoxysilane is up to ca. 90% after 7 h at 90℃, and no solvent is used for this reaction. In the presence of organic amine, the reaction gives formamide or urea instead of methoxysilane. Under 1.5 MPa CO2, 1.0 mol% ZnEt2, 2.4 equiv. (EtO)3SiH and 100℃, a series of secondary amines, both the aromatic ones and the aliphatic ones, can be formylated into formamides. In the formylation of N-methylanilines with different substituents at para-position, the isolated yields of the formylation products are in the order of OMe≈Me>H>F>Cl≈Br>CF3>NO2, indicating the electron-donating group at the para-position of the N-methylanilines is benefit for the formylation reaction. When primary amines are used as the substrates, the reactions prefer to produce urea derivatives under the same reaction conditions. In the urealation reaction, the electronic effect is not as significant as that in the formylation reaction.

Key words: ZnEt2, carbon dioxidetransformation, hydrosilylation, formamides, ureas