Stereocontrolled polymerization of racemic lactide with chiral initiator: combining stereoelection and chiral ligand-exchange mechanism

Katarzyna Majerska; Andrzej Duda

doi:10.1021/ja0388966

Stereocontrolled polymerization of racemic lactide with chiral initiator: combining stereoelection and chiral ligand-exchange mechanism

J Am Chem Soc. 2004 Feb 4;126(4):1026-7. doi: 10.1021/ja0388966.

Authors

Katarzyna Majerska¹, Andrzej Duda

Affiliation

¹ Department of Polymer Chemistry, Center of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, PL-90-363 Lodz, Poland.

PMID: 14746463
DOI: 10.1021/ja0388966

Abstract

New opportunities, provided by the 2,2'-[1,1'-binaphthyl-2,2'-diylbis(nitrylomethilidyne)]diphenol (SB(OH)2)/Al(OiPr)3/racemic lactide (rac-LA) polymerization system, employing a combination of stereoelection with (S) and (R) ligand-exchange mechanism at Al-alkoxide active centers were explored. The stereoelectivity was comparable to that determined for the process with an additional synthetic step of isolation and purification of the SBO2Al-OiPr alkoxide. The resultant poly(rac-LA) had a gradient stereocopolymer structure and exhibited enhanced thermal stability due to a stereocomplex formation (Tm = 210 degrees C). This is the highest melting temperature reported until now for poly(lactide) (PLA) prepared directly from rac-LA.