Monomer versus alcohol activation in the 4-dimethylaminopyridine-catalyzed ring-opening polymerization of lactide and lactic O-carboxylic anhydride

被引：94

作者：

Bonduelle, Colin ^{[2
]}

Martin-Vaca, Blanca ^{[2
]}

Cossio, Fernando P. ^{[1
]}

Bourissou, Didier ^{[2
]}

机构：

[1] Univ Basque Country, Fac Quim, Dept Quim Organ 1, Euskal Herriko Unibertsitatea, San Sebastian 20080, Donostia, Spain

[2] Univ Toulouse 3, CNRS, Equipe Ligands Bifonct & Polymeres Biodegradables, Lab Heterochim Fondamentale & Appl,UMR 5069, F-31062 Toulouse, France

来源：

CHEMISTRY-A EUROPEAN JOURNAL | 2008年 / 14卷 / 17期

关键词：

density functional calculations; dimethylaminopyridine; hydrogen bonds; organocatalysis; ring-opening polymerization;

D O I：

10.1002/chem.200800346

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Model reactions for the 4-dimethylaminopyridine (DMAP)-catalyzed ring-opening polymerization of lactide and the corresponding lactic O-carboxylic anhydride (lacOCA) have been studied computationally at the B3LYP/6-31G(d) level of theory. The solvent effect of dichloromethane was taken into account through PCM/SCRF single-point calculations at the B3LYP/6-31G(d) level of theory. In marked contrast with that predicted for the reaction of alcohols with acetic anhydride, the mechanism in which nucleophilic activation of the monomer involving acylpyridinium intermediates was found to be energetically less favorable than the base activation of the alcohol through hydrogen bonding. The concerted pathway for the ring-opening of lactide and lacOCA was shown to compete with the traditional stepwise mechanism involving tetrahedral intermediates. Furthermore, DMAP is proposed to act as a bifunctional catalyst through its basic nitrogen center and an acidic ortho-hydrogen atom.

引用

页码：5304 / 5312

页数：9

共 106 条

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