Hydrogen-bonding activation carbonyl compounds, asymmetric

Activation of carbonyl compounds by double hydrogen bonding an emerging tool in asymmetric catalysis (P. M. Pihko, 2004) [lb]. 

Organocatalysed asymmetric Michael addition has been extensively studied because of the interest in the adducts as valuable intermediates in organic synthesis. The use of a carbonyl compound as donor and prolinamides as catalysts supposes the formation of the corresponding enamine which adds to the a,p-unsaturated compound activated by formation of hydrogen bonds with the carboxamide substituent. In general, the major diastereoisomer has syn configuration because the enamine attacks from its re-face to the re-face of the double bond (Scheme 6.2). 

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