Highly Syndiotactic or Isotactic Polyhydroxyalkanoates by Ligand-Controlled Yttrium-Catalyzed Stereoselective Ring-Opening Polymerization of Functional Racemic ß-Lactones.
Angew Chem Int Ed Engl
; 56(35): 10388-10393, 2017 08 21.
Article
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| MEDLINE
| ID: mdl-28666071
Reported herein is the first stereoselective controlled ROP of a specific family of racemic functional ß-lactones, namely 4-alkoxymethylene-ß-propiolactones (BPLOR s). This process is catalyzed by an yttrium complex stabilized by a nonchiral tetradentate amino alkoxy bisphenolate ligand {ONOOR'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 (Ps up to 0.91 with R'=cumyl) to very high isoselectivity (Pi 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 ß-lactone.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2017
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Alemania