Organocatalyzed step-growth polymerization through desymmetrization of cyclic anhydrides: synthesis of chiral polyesters.

The polymerization of prochiral bis-anhydrides with diols catalyzed by a cinchona alkaloid was shown to provide chiral polyesters in good yields and with high levels of stereocontrol. The structures of the polyesters were determined by (1) H and (13) C NMR analyses, whereas their size was estimated by both size-exclusion chromatography (SEC) and MALDI-TOF mass spectrometry, which indicated that moderate degrees of polymerization were attained through this step-growth polymerization. The enantioselectivity of the process was evaluated by using chiral HPLC analysis of the bis-lactones resulting from a controlled chemoselective degradation of the polyesters. The best stereocontrol was reached for oligomers formed from bis-anhydride and diol monomers bearing rigid aromatic spacers between the reactive functional groups. In this case, average enantioselectivities were comparable to those observed during ring-opening of simple anhydrides with similar alcohols. In contrast, the use of more flexible spacers between reactive entities generally led to lower levels of stereocontrol. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Anthony Martin, Frédéric Robert, Daniel Taton, Henri Cramail, Jean-Marc Vincent, Yannick Landais. Organocatalyzed step-growth polymerization through desymmetrization of cyclic anhydrides: synthesis of chiral polyesters. Chemistry (Weinheim an der Bergstrasse, Germany). 2014 Sep 8;20(37):11946-53

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PMID: 25078099

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