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DOI: 10.1055/s-2007-992517
Morita-Baylis-Hillman Reaction Catalyzed by MNP-Supported Quinuclidine
Contributor(s):Yasuhiro Uozumi, Yohei OeBeijing National Laboratory for Molecular Sciences and Nankai University, Tianjin, P. R. of China
Magnetic Nanoparticle-Supported Morita-Baylis-Hillman Catalysts
Adv. Synth. Catal. 2007, 349: 2431-2434
Publication History
Publication Date:
23 January 2008 (online)
Key words
Morita-Baylis-Hillman reaction - magnetic nanoparticles - quinuclidines
Significance
A magnetic nanoparticle (MNP)-supported quinuclidine catalyst for the Morita-Baylis-Hillman (MBH) reactions was described. Thus, MNP-supported quinuclidine 2 was prepared by treatment of triethoxysilane 1 with polyvinylpyrrolidone-protected MNP in refluxing toluene (eq. 1). The MBH reactions of acrylates or acrylonitrile 3 with aldehydes 4 were performed in the presence of 2 in catalytic amounts to give the corresponding adducts 5 in 62-99% yield (eq. 2).
Comment
The catalytic activity of 2 is comparable to the traditional catalyst for the MBH reactions, DABCO, and higher than the corresponding silica-supported quinuclidine. Catalyst 2 can be readily separated from the reaction mixture by using an external magnet and can be reused five times without significant loss of catalytic activity (for the reaction of acrylonitrile with 4-nitrobenzaldehyde, 1st use: 88% yield, 2nd use: 87% yield, 3rd use: 88% yield, 4th use: 88% yield, 5th use: 85% yield); however, a slight decrease of catalytic activity was observed in the 6th recycling run (79% yield).