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Highly Syndiotactic or Isotactic Polyhydroxyalkanoates by Ligand‐Controlled Yttrium‐Catalyzed Stereoselective Ring‐Opening Polymerization of Functional Racemic β‐Lactones
Author(s) -
Ligny Romain,
Hänninen Mikko M.,
Guillaume Sophie M.,
Carpentier JeanFrançois
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201704283
Subject(s) - stereoselectivity , ligand (biochemistry) , yttrium , tacticity , alkoxy group , polymerization , catalysis , chemistry , lactide , ring (chemistry) , stereochemistry , polymer , organic chemistry , receptor , oxide , biochemistry , alkyl
Abstract 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.