Abstract:Trans-N-Boc-4-hydroxy-L-prolin-methylester was used to prepare Corey-Bakshi-Shibata (CBS) catalyst precursor and poly(divinylbenzene) (P(DVB)) microsphere with reversible addition-fragmentation chain transfer (RAFT) end groups was obtained via RAFT precipitation polymerization. Then the CBS catalyst precursor and styrene were grafted onto the surface of P(DVB) microsphere by random copolymerization. Moreover, methylboronic acid was used to condense with CBS catalyst precursor on P(DVB) microsphere and hairy particle-supported CBS catalyst was obtained. The structure and morphology of functional hairy particle were characterized by Nuclear Magnetic Resonance (1H-NMR), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The preparation of polymer brushes using RAFT technology can effectively control the degree of graft polymerization and avoid polymer chain agglomeration, making the hairy particle-supported CBS catalyst stably dispersed in the reaction medium. The obtained hairy particle-supported CBS catalyst was used to catalyze the asymmetric reduction of acetophenone and the catalytic activity and stereoselectivity of the catalyst were investigated. The results showed that the catalyst not only had the advantages of easy separation of heterogeneous CBS catalysts, but also had the catalytic properties of homogeneous CBS catalysts with high selectivity and high conversion. In the asymmetric reduction of acetophenone, with the increase of mole fraction of catalyst precursor, the enantiomeric excess (ee) value of the product phenylethanol showed an increasing trend. When the molar fraction of catalyst precursor exceeded 40%, the supported catalyst had excellent catalytic effect. Moreover, the catalytic activity did not significantly decrease after five cycles. The ee value of the product phenylethanol was up to 93% and the conversion of acetophenone approached 100%.