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Azaphosphatranes as Hydrogen‐Bonding Organocatalysts for the Activation of Carbonyl Groups: Investigation of Lactide Ring‐Opening Polymerization
Author(s) -
Zhang Dawei,
Jardel Damien,
Peruch Frédéric,
Calin Nathalie,
Dufaud Véronique,
Dutasta JeanPierre,
Martinez Alexandre,
Bibal Brigitte
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201600080
Subject(s) - chemistry , polymerization , polymer chemistry , ring opening polymerization , hydrogen bond , steric effects , lactide , organocatalysis , catalysis , epoxide , amine gas treating , organic chemistry , polymer , molecule , enantioselective synthesis
The hydrogen‐bonding activation of C=O bonds by azaphosphatranes was explored in a model reaction, i.e., the ring‐opening polymerization of lactide. The polymerization process was controlled, and allowed the preparation of polylactides with narrow dispersity under mild conditions (20 °C, 24 h, 10 mol‐% catalyst loading). Interestingly, the steric hindrance of azaphosphatranes, as globular rigid structures, prevents any undesired interaction with the tertiary amine cocatalysts, as shown by X‐ray analysis and semi‐empirical calculations. In contrast to their organocatalytic activity in the CO 2 /epoxide reaction, all of the phosphonium derivatives tested were found to be efficient catalysts in this ROP benchmark reaction.