Michael reaction scaffold structures

The higher activity of primary amines in the reaction involving enones as Michael acceptors has also been extended to the use of different bifunctional catalysts (Scheme 3.19), which usually contain a primary amine functionality connected to a basic site by means of a chiral scaffold, as is the case in the use of 280 and 55. These diamine catalysts have been found to be excellent promoters of the Michael reaction of enones with cyclic 1,3-dicarbonyl compounds and malonates respectively, the tertiary amine basic site present at the catalyst structure being responsible for assisting in the deprotonation of the Michael donor in order to increase the concentration of the nucleophile species. In a different approach, bifunctional thiourea-primary amine catalyst 56a has also... 

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