Enantioselective decarboxylative michael and aldol reactions with bifunctional squaramide organocatalysts

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2018
Bayer, Ezgi
The decarboxylative Michael and aldol reactions are quite new in the asymmetric studies and are used for forming new C-C bonds by nucleophilic attack. In the first part of this thesis, decarboxylative Michael reaction of isatylidene malononitriles with ethyl benzoyl acetate was accomplished in the presence of chiral 2- aminoDMAP and quinine derived bifunctional acid/base organocatalysts, which are developed in our research group. In this part, 12 derivatives were synthesized with quinine based 1-adamantyl squaramide bifunctional organocatalyst up to 46% ee under the optimized condition with 10 mol% catalysts loading at -20 °C. In the second part, the enantioselective decarboxylative aldol reactions of α- amidohemimalonates with various aldehydes were accomplished in the presence of the organocatalysts developed in our research group. In this part, the best result was achieved with 10 mol% t-butyl squaramide quinine organocatalyst as 63% ee.