Reactions of 2,2‘-Methylenebis(4-chloro-6-isopropyl-3-methylphenol) and 2,2‘-Ethylidenebis(4,6-di-tert-butylphenol) with MgnBu2:  Efficient Catalysts for Ring-Opening Polymerization of ε-Caprolactone andl-Lactide

Three novel magnesium aryloxides, (MCIMP) 2 Mg 2 (THF) 2 ( 1 ), (EDBP)Mg(Et 2 O) 2 ( 2 ), and (EDBP)Mg(THF) 2 ( 3 ), have been synthesized by the reaction of 2,2‘-methylenebis(4-chloro-6-isopropyl-3-methylphenol) (MCIMP−H 2 ) or 2,2‘-ethylidenebis(4,6-di- tert -butylphenol) (EDBP−H 2 ) with Mg n Bu 2 in diethyl ether or tetrahydrofuran, respectively. Experimental results show that 1 − 3 efficiently catalyze the ring-opening polymerization of ε-caprolactone and l -lactide in a controlled fashion, yielding polymers with very narrow polydispersity indexes in a wide range of monomer-to-initiator ratios. Compound 1 has paved a way to synthesize as much as 500-fold polymer chains of poly(ε-caprolactone) with a very narrow polydispersity index. In addition, block copolymers such as poly(ε-caprolactone)- b -poly( l -lactide), poly(ethylene glycol) methyl ether- b -poly( l -lactide), and polystyrene- b -poly( l -lactide) have also been prepared.