Ernst Schering Foundation Symposium Proceedings, Vol. 2, pp. 299–319
DOI 10.1007/2789_2007_067
© Springer-Verlag Berlin Heidelberg
Published Online: 18 December 2007
Recoverable, Soluble Polymer-Supported
Organic Catalysts
M. Benaglia
(u)
Dipartimento di Chimica Organica e Industriale, Universita’ degli Studi di Milano, Via C.
Golgi 19, 20133 Milan, Italy
email: maurizio.benaglia@unimi.it
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
2
General Considerations on the Immobilization Process . . . . . . . 302
3
Achiral Organic Catalysts . . . . . . . . . . . . . . . . . . . . . . 307
3.1
Oxidation Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . 307
3.2
Phase-Transfer Catalysts . . . . . . . . . . . . . . . . . . . . . . 308
4
Chiral Organic Catalysts . . . . . . . . . . . . . . . . . . . . . . . 311
4.1
Proline-Derived Catalysts . . . . . . . . . . . . . . . . . . . . . . 311
4.2
MacMillan’s Catalyst . . . . . . . . . . . . . . . . . . . . . . . . 314
5
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Abstract. Enantioselective organic catalysis is currently the subject of an intense research activity aimed to develop ‘metal-free’ alternatives to established
‘metal-based’ catalytic processes. In the case of chiral catalysts, which are often
expensive, or obtained after a complex synthesis, the immobilization on solid
support represents an attractive methodology that allows the recovery and possibly the recycling of the catalytic species. Among the different solid matrixes
employed, soluble polymers recently emerged as very convenient supports for
the synthesis of a variety of small organic molecules, ligands and catalysts. This
chapter highlights the more recent results obtained by our group in the field
of poly(ethylene glycol) (PEG)-supported chiral and achiral organic catalysts.
A few considerations on the methodologies, the future and the problems related
to the immobilization of chiral organic catalysts are also briefly discussed.
DOI 10.1007/2789_2007_067
© Springer-Verlag Berlin Heidelberg
Published Online: 18 December 2007
Recoverable, Soluble Polymer-Supported
Organic Catalysts
M. Benaglia
(u)
Dipartimento di Chimica Organica e Industriale, Universita’ degli Studi di Milano, Via C.
Golgi 19, 20133 Milan, Italy
email: maurizio.benaglia@unimi.it
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
2
General Considerations on the Immobilization Process . . . . . . . 302
3
Achiral Organic Catalysts . . . . . . . . . . . . . . . . . . . . . . 307
3.1
Oxidation Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . 307
3.2
Phase-Transfer Catalysts . . . . . . . . . . . . . . . . . . . . . . 308
4
Chiral Organic Catalysts . . . . . . . . . . . . . . . . . . . . . . . 311
4.1
Proline-Derived Catalysts . . . . . . . . . . . . . . . . . . . . . . 311
4.2
MacMillan’s Catalyst . . . . . . . . . . . . . . . . . . . . . . . . 314
5
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Abstract. Enantioselective organic catalysis is currently the subject of an intense research activity aimed to develop ‘metal-free’ alternatives to established
‘metal-based’ catalytic processes. In the case of chiral catalysts, which are often
expensive, or obtained after a complex synthesis, the immobilization on solid
support represents an attractive methodology that allows the recovery and possibly the recycling of the catalytic species. Among the different solid matrixes
employed, soluble polymers recently emerged as very convenient supports for
the synthesis of a variety of small organic molecules, ligands and catalysts. This
chapter highlights the more recent results obtained by our group in the field
of poly(ethylene glycol) (PEG)-supported chiral and achiral organic catalysts.
A few considerations on the methodologies, the future and the problems related
to the immobilization of chiral organic catalysts are also briefly discussed.