Facile Synthesis of Functionalized Lactones and Organocatalytic Ring-Opening Polymerization

A facile one-step synthesis of functionalized valerolactones was carried out by the conjugate addition of thiols to the alpha,beta-unsaturated valerolactone 5,6-dihydro-2H-pyran-2-one. The resultant 3-mercaptovalerolactones undergo ring-opening polymerization in solution or in the melt to generate polyesters functionalized either with benzyl mercaptans or oligoethylene glycol pendant groups. The copolymerization of the 3-mercaptovalerolactones with epsilon-caprolactone generates random copolymers.