Rapid one-pot catalytic synthesis of double-capped oligoesters from lactones

Abstract

© 2017 Elsevier B.V. The rapid one-pot catalytic synthesis of double-capped oligoesters was carried out by the ring-opening polymerization of various cyclic ester monomers (i.e. ε-caprolactone (ε-CL), δ-valerolactone (DVL), γ-butyrolactone (GBL), and L-lactide (L-LA)) followed by the transesterification reaction with a variety of alkyl esters as an end-capping agent. Simple metal amides were found to be an effective catalyst under mild condition. Among them, LiN(SiMe3)2 was shown to be the most active catalyst giving 94% conversion of double-capped oligo(ε-caprolactone) within 5 min at room temperature. The average chain length of the oligoesters can be controlled by the adjustment of the ratio of an alkyl ester to monomer, the reaction time and reaction temperature.