Highly stereoselective hydrogenation of α‑pinene over Ir nanoparticles confined in SiO2 shells

Ir@mSiO2 catalyst prepared by one pot method. High selectivity and activity in hydrogenation of α-pinene to cis-pinane near room temperature. Ir@mSiO2 catalysts exhibited a higher stability compared to other support catalysts. [Display omitted] •Core-shell Ir@mSiO2 catalysts was synthesized by sol–gel method.•High stereoselectivity and activity for cis-pinane near room temperature.•Stable adsorption of α-pinene on Ir metal edge sites.•The adsorption mode of α-pinene was verified through DFT. The highly stereoselective hydrogenation of α-pinene was very important and challenging in the utilization of natural products at mild conditions. Here, we reported a core–shell catalyst coated with Ir metal particles by mesoporous silica shell, and revealing the dependence of reducing agents during the preparation process. The prepared nano catalyst exhibited excellent performance in the hydrogenation of chiral substance α-pinene, especially under very mild conditions (40 °C, 1 MPa H2 and 2 h), with a yield of cis-pinane reaching ∼99 %. The characterization methods revealed that the excellent performance was attributed to the strong hydrogenolysis ability of Ir particles. DFT results further indicated that α-pinene can stably adsorb on the edge sites of Ir metal in a cis structure, thereby achieving highly stereoselective hydrogenation. This work utilized heterogeneous catalysis to achieve performance close to that of homogeneous catalysts. The stable core shell structure greatly prolonged the lifespan of the catalyst and overcame the drawbacks of homogeneous catalysts. This work provided more reference cases for chiral hydrogenation.