摘要
Heterogeneous catalysis for organic synthesis under continuous-flow conditions becomes possible by a new reactor-based approach. Continuous-flow reactors with a monolithic glass/polymer composite interior are loaded with palladium particles by ion exchange followed by reduction. When incorporated into a continuous-flow setup (PASSflow) this reactor allows the transfer-hydrogenation of alkenes, alkynes, nitro-substituted aromatic compounds and benzyl ethers in the flow-through mode. In addition, the activity of the catalysts is well suited to achieve Suzuki, Sonogashira and Heck cross-coupling reactions in the absence of phosphanes or any other ligands, resulting in a greatly simplified purification. As an extension to this concept a bifunctional support was prepared inside the reactor consisting of Pd particles and an ion-exchange group (hydroxide form). In the Suzuki-Miyaura reaction the reactor serves as a base for immobilisation and activation of the boronic acid as boronate and as a catalyst for promoting the C-C coupling reaction under continuous-flow conditions.
- 出版日期2004-8-27