Catalytic reactions Knoevenagel reaction, amino acids

Further projects dealt with the fabrication of heterogeneous, basic or acidic solid-state catalysts or adsorbents carrying, for instance, amino or sulfonic acid groups. Amino-functionalized silicas were prepared and analyzed for the catalytic activity in Knoevenagel condensation reactions of aldehydes or ketones with ethyl cyanoace-tate ions by Macquarrie et al.154 155 Recently, Zhang et al.156,157 reported on the successful preparation of amino-functionalized silica thin films by means of the EISA approach. 

On the basis of the proposed catalytic cycle, aldehyde 9 reacts with 1,3-indandione 178 by amine-catalyzed Knoevenagel condensation to provide the benzylidene-indandione B via iminium ion A, which is an excellent organic Lewis acid. This intermediate thns undergoes a Diels-Alder or a double Michael reaction with the soft nucleophile 2-amino-1,3-butadiene C generated in situ from enone 84 and the amine catalyst to produce the... 

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