Abstract
Highly active yttrium phosphasalen initiators for the stereocontrolled ring-opening polymerization of rac-lactide are reported. The initiators are coordinated by a new class of ancillary ligand: an iminophosphorane derivative of the popular "salen" ligand, termed "phosphasalen". Changing the phosphasalen structure enables access to high iso-selectivities (Pi = 0.84) or hetero-selectivities (Ps = 0.87). The initiators also show very high rates, excellent polymerization control, and tolerance to low loadings; furthermore, no chiral auxiliaries/ligands are needed for the stereocontrol. The combination of such high rates with high iso-selectivities is very unusual.
Original language | English |
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Pages (from-to) | 20577-20580 |
Number of pages | 4 |
Journal | Journal of the American Chemical Society |
Volume | 134 |
Issue number | 51 |
DOIs | |
Publication status | Published - 26 Dec 2012 |