Multistep Organic Transformations over Base-Rhodium/ Diamine-Bifunctionalized Mesostructured Silica Nanoparticles

作者：Liao, Hang; Chou, Yajie; Wang, Yu; Zhang, Han; Cheng, Tanyu; Liu, Guohua^*

来源：ChemCatChem, 2017, 9(16): 3197-3202.

DOI：10.1002/cctc.201700436

• asymmetric catalysis
• heterogeneous catalysis
• immobilization
• rhodium
• supported catalysts

The assembly of multiple catalytic functionalities within a single mesoporous silica as a catalyst for multistep enantioselective organic transformations in an environmentally friendly medium is a significant challenge in heterogeneous asymmetric catalysis. Herein, we took advantage of a BF4 anion hydrogen bonding strategy to anchor a chiral cationic rhodium/diamine complex within base-functionalized mesostructured silica nanoparticles conveniently to construct a bifunctional heterogeneous catalyst. The solid-state C-13 NMR spectrum discloses the well-defined chiral Rh/diamine active species, and we used XRD, N-2 adsorption-desorption, and electron microscopy to reveal the ordered mesostructure. The combination of bifunctionality in the silica nanoparticles enables two kinds of efficient enantioselective organic transformations with high yields and enantioselectivities, in which the asymmetric transfer hydrogenation of alpha-haloketones followed by epoxidation provides various chiral aryloxiranes, and the amination of alpha-haloketones with anilines followed by asymmetric transfer hydrogenation produces various beta-amino alcohols. Furthermore, the catalyst can be recovered and recycled for seven times without a loss of catalytic activity, which is an attractive feature for multistep organic transformations in a sustainable benign process.

• 出版日期2017-8-23
• 单位上海师范大学