Highly Syndiotactic or Isotactic Polyhydroxyalkanoates by Ligand-Controlled Yttrium-Catalyzed Stereoselective Ring-Opening Polymerization of Functional Racemic β-Lactones.

Autor: Ligny R; Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, 35042, Rennes, France., Hänninen MM; Department of Chemistry, University of Jyväskylä, Jyväskylä, P.O. Box 35, 40014, Finland., Guillaume SM; Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, 35042, Rennes, France., Carpentier JF; Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, 35042, Rennes, France.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2017 Aug 21; Vol. 56 (35), pp. 10388-10393. Date of Electronic Publication: 2017 Jul 25.
DOI: 10.1002/anie.201704283
Abstrakt: Reported herein is the first stereoselective controlled ROP of a specific family of racemic functional β-lactones, namely 4-alkoxymethylene-β-propiolactones (BPL OR s). This process is catalyzed by an yttrium complex stabilized by a nonchiral tetradentate amino alkoxy bisphenolate ligand {ONOO R'2 } 2- , which features both a good activity and a high degree of control over the molar masses of the resulting functional poly(3-hydroxyalkanoate)s. A simple modification of the R' substituents in ortho and para position on the ligand platform allows for a complete reversal from virtually pure syndioselectivity (P s up to 0.91 with R'=cumyl) to very high isoselectivity (P i up to 0.93 with R'=Cl), as supported by DFT insights. This is the first example of a highly isoselective ROP of a racemic chiral β-lactone.
(© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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