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Engineering Polymer‐Enhanced Bimetallic Cooperative Interactions in the Hydrolytic Kinetic Resolution of Epoxides
Author(s) -
Zheng Xiaolai,
Jones Christopher W.,
Weck Marcus
Publication year - 2008
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200700339
Subject(s) - kinetic resolution , chemistry , bimetallic strip , catalysis , cobalt , styrene , hydrolysis , monomer , ethylene glycol , synergistic catalysis , polymer chemistry , polymer , molecule , copolymer , combinatorial chemistry , organic chemistry , enantioselective synthesis
Through systematic variations of the length of oligo(ethylene glycol)‐based linkers and the catalyst density of poly(styrene)‐supported cobalt‐salen catalysts, we have elucidated an optimal catalyst flexibility and density of polymeric Co‐salen catalysts for the hydrolytic kinetic resolution (HKR) of racemic terminal epoxides that follows a bimetallic cooperative pathway. The optimized polymeric catalyst brings the two cooperative Co‐salen units to a favorable proximity efficiently and hence displays significantly improved catalytic performance in the HKR compared with its monomeric small molecule analogue. Complex Co(5b) , representing the most active poly(styrene)‐supported HKR catalyst known so far, can effect the resolution of a variety of epoxides to reach ≥98 % ee in 6–24 h with a low cobalt loading of 0.01–0.1 mol %.