Intermolecular Domino Michael Additions of Other-than-C-Nucleophiles

6 Intermolecular Domino Michael Additions of Other-than-C-Nucleophiles 

This catalyst was also applied by Cordova et al. to an enantio-selective aminosulfenylation of ot,p-unsaturated aldehydes, which gave access 

The second class of chiral organocatalysts recently involved in domino Michael reactions of other-than-C-nucleophiles is constituted by the cinchona alkaloid family. In this area, Melchiorre et al. have involved a chiral primary amine salt derived from 9-amino-(9-deoxy)-epz-hydroquinine to induce chirality in aziridinations of enones. This domino iminium-enamine intramolecular sequence afforded a series of chiral protected aziridines derived from both 

A closely related methodology was applied by Zhao et al. to the enantio-selective synthesis of tetrasubstituted thiochromanes on the basis of a domino thia-Michael-Knoevenagel reaction between 2-mercaptobenzaldehydes and benzylidenemalonates with the same quinine thiourea catalyst. Steric and electron effects were found to affect profoundly the stereoselectivities of the reaction. Thus, it was shown that the diastereoselectivity of the reaction 

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