Yttrium-Mediated Ring-Opening Copolymerization of Oppositely-Configurated 4-Alkoxymethylene-β-Propiolactones. Effective Access to Highly Alternated Isotactic Functional PHAs - Université de Rennes Access content directly
Journal Articles Chemistry - A European Journal Year : 2019

Yttrium-Mediated Ring-Opening Copolymerization of Oppositely-Configurated 4-Alkoxymethylene-β-Propiolactones. Effective Access to Highly Alternated Isotactic Functional PHAs

Abstract

The ring-opening copolymerization (ROCOP) of functional 4-alkoxymethylene-β-propiolactones (BPL s) by yttrium-bisphenolate complexes was investigated. The ROCOP of equimolar mixtures of BPL s of opposite configurations, namely (R)-BPL /(S)-BPL [R , R =OMe, OAllyl, OCH Ph (=OBn), OSiMe tBu (=OTBDMS)], by the syndioselective Y{ONOO }/iPrOH catalyst/initiator system affords P(HB -alt-HB ) copolymers with high alternation degrees (altern.=89-94 %), as determined by comprehensive kinetic, C{ H} NMR spectroscopy, MALDI-ToF MS and ESI MS/MS fragmentation studies. The ROCOP of the (R)-BPL /(S)-BPL combination, featuring a large difference in the substituents' bulkiness, constitutes the only observed exception to this trend (altern.=64 %). On the other hand, the isoselectivity of the Y{ONNO }/iPrOH catalyst/initiator system has been exploited to generate, in a one-pot/one-step procedure, original mixtures of isotactic poly(hydroxyalkanoate)s (PHAs). This system efficiently transforms equimolar mixtures of (R)-BPL /(S)-BPL into a 1:1 mixture of the corresponding isotactic iso-(R)-PHB and iso-(S)-PHB homopolymers; almost no copolymerization defects are observed. This new approach has been extended successfully to the ROCOP of equimolar mixtures of racemic monomers, rac-BPL /rac-BPL .
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Dates and versions

hal-02050275 , version 1 (13-03-2019)

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Romain Ligny, Sophie M. Guillaume, Jean-Francois Carpentier. Yttrium-Mediated Ring-Opening Copolymerization of Oppositely-Configurated 4-Alkoxymethylene-β-Propiolactones. Effective Access to Highly Alternated Isotactic Functional PHAs. Chemistry - A European Journal, 2019, 25 (25), pp.6412-6424. ⟨10.1002/chem.201900413⟩. ⟨hal-02050275⟩
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