Increased Lewis acidity in hafnium-substituted polyoxotungstates

被引：74

作者：

Boglio, Cecile

Micoine, Kevin

Remy, Pauline

Hasenknopf, Bernold

Thorimbert, Serge

Lacote, Emmanuel

Malacria, Max

Afonso, Carlos

Tabet, Jean-Claude

机构：

[1] Univ Paris 06, UMR CNRS 7611, Inst Chim Mol, Lab Chim Organ,FR 2769, F-75005 Paris, France

[2] Univ Paris 06, UMR CNRS 7071, Inst Chim Mol, Lab Chim Inorgan & Mat Mol,FR 2769, F-75005 Paris, France

[3] Univ Paris 06, UMR CNRS 7613, Inst Chim Mol, Lab Struct & Fonct Mol Bioact,FR 2769, F-75005 Paris, France

来源：

CHEMISTRY-A EUROPEAN JOURNAL | 2007年 / 13卷 / 19期

关键词：

aldol reaction; hafnium; imines; Lewis acids; polyoxometalates;

D O I：

10.1002/chem.200700010

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Monolacunary polyoxotungstates [alpha(1)-P2W17O61](10-) and [alpha-PW11O39](7-) react with HfCl4 to yield [alpha(1)-HfP2W17O61](6-) and [alpha-Hf(OH)P-W11O39](4-), isolated as organo-soluble tetrabutylammonium (TBA) salts. Subsequent analyses, including mass spectrometry, show that they are stronger Lewis acids than (TBA)(5)H-2[alpha(1)-YbP2W17O61]. The new polyoxotungstates catalyze Lewis acid mediated organic reactions, such as Mukaiyama aldol and Mannich-type additions. In particular, reactions with aldehydes, which were impossible with lanthanide polyoxotungstates, are made possible. Thus these modifications of the polyoxometalate composition allowed fine tuning of the Lewis acidity. The catalysts could be easily recovered and reused.

引用

页码：5426 / 5432

页数：7

共 36 条

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