RSS-Feed abonnieren
DOI: 10.1055/s-0029-1218447
Asymmetric Aldol Reaction with Polystyrene-Supported Proline-Based Catalysts
M. Gruttadauria*, A. M. P. Salvo, F. Giacalone, P. Agrigento, R. Noto
Università di Palermo, Italy
Publikationsverlauf
Publikationsdatum:
21. Dezember 2009 (online)
Significance
Polystyrene-supported prolinamide was prepared and applied to the asymmetric direct aldol reaction in water. Thus, etherification of N-Boc-protected trans-4-hydroxy-proline 1 with vinylbenzyl chloride followed by condensation with (1S,2R)-(-)-1-amino-2-indanol gave dipeptide 3 in 40% yield over two steps. The thiolene coupling reaction of the dipeptide 3 with mercaptomethyl-polystyrene resin afforded the polymer-supported dipeptide, which was deprotected with TFA and washed with THF-Et3N to furnish the polystyrene-supported prolinamide 4. Asymmetric aldol reaction of cyclohexanone (5) with 4-nitro-benzaldehyde (6) was carried out with the polymeric catalyst 4 to give the aldol product 7 in high yield with 72% ee. This catalyst was recovered and reused three times without any loss of catalytic activity.