Dienamine covalent catalysis

The enantioselective organocatalytic functionaUzation of carbonyl compounds at the 7 position represents a highly challenging and persistent problem for asymmetric synthesis [33]. Recently, Melchiorre and coworkers [34] reported a chiral Bronsted acid-assisted dienamine catalysis for the direct asymmetric y-alkylation of a-substituted linear a,(l-unsaturated aldehydes (Scheme 43.22). In this reaction, the chiral phosphoric acid 106 can induce the formation of a chiral contact ion-pair from alcohol 103 [35], which may synergistically engage in a matched combination with the chiral covalent dienamine intermediate derived from chiral primary... 

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