Linear and three-arm star hydroxytelechelic poly(benzyl β-malolactonate)s: a straightforward one-step synthesis through ring-opening polymerization

Ghislaine Barouti (1) , Cedric G. Jaffredo (1) , Sophie M Guillaume (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

Ring-opening polymn. (ROP) of racemic-benzyl β-malolactonate (MLABe) initiated by an alc. such as 1,3-propanediol (PPD) or 2-hydroxymethyl-1,3-propanediol (TMM), and catalyzed by a metal triflate M(OTf)3 with M = Nd, Bi, proceeded under mild operating conditions (in bulk at 60 °C). The functionality of the alc. dictates the topol. of the resulting hydroxy telechelic PMLABe. The ROP promoted by the neodymium-based catalytic system afforded a satisfactory activity and control in terms of molar mass and dispersity values (Mn,NMR up to 7000 g mol-1, DM \textless 1.35). Mechanistic insights revealed that ring-opening of MLABe took place through the selective oxygen-acyl bond cleavage without undesirable side reactions such as transesterification or crotonisation, as evidenced by NMR and mass spectrometry analyses of the recovered polyesters. The structure of the corresponding α,ω-hydroxy telechelic PMLABes was ascertained by 1H and 13C\1H\ NMR, SEC, and MALDI-ToF mass spectrometry analyses. In comparison, methane and trifluoromethane sulfonic acids did not allow the formation of well-defined PMLABe diols. Differences in the behavior of MLABe and the related β-butyrolactone are highlighted. The present Nd(OTf)3/PPD or TMM catalytic ROP of MLABe thus represents a valuable direct synthesis of PMLABe diols and triols, resp., without requiring chem. modification of a preformed PMLABe precursor.

Domaines: Chimie

Ghislaine Barouti, Cedric G. Jaffredo, Sophie M Guillaume. Linear and three-arm star hydroxytelechelic poly(benzyl β-malolactonate)s: a straightforward one-step synthesis through ring-opening polymerization. Polymer Chemistry, 2015, 6 (32), pp.5851-5859. ⟨10.1039/C5PY00724K⟩. ⟨hal-01188240⟩