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