Asymmetric Catalysis with Covalent Interactions

From a mechanistic viewpoint, asymmetric Friedel-Crafts alkylation (AFCA) reactions are similar to the historical version, with the chiral additives responsible for triggering and controUing the overall aromatic C—H replacement. Interestingly, covalent (organocatalysis) or noncovalent (metal catalysis) interactions can take place between catalysts and electrophiles during the enantiodis-criminating step of the reaction course (Fig. 5.1). 

This work represents a landmark in the area of stereoselective metal-free (i.e., aminocatalysis) alkylation of benzenes based on Michael-type condensation via covalent catalyst-substrate interaction [22]. Subsequently, asymmetric acid catalysis based on hydrogen bond catalyst-substrate recognitions has found elegant applications in 1,4-conjugated additions and direct condensation of arenes with carbonyl compounds. The following sections will be organized based on the reactivity exploited in the arene functionalization. 

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