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Abstract:
This Ph.D. work describes the development of catalytic asymmetric organic reactions via aminocatalysis. In the first part, the catalytic asymmetric Knoevenagel condensation reaction via iminium-enamine catalysis is presented. The first asymmetric variant of the Knoevenagel condensation reaction was realized using a newly developed cinchona derived amine catalyst. A broad range of α-branched aldehydes were applied to the reaction with good to excellent yields and enantioselectivities. The second part of this thesis describes a highly efficient catalytic asymmetric epoxidation of 2-cyclopentenones. The cinchona derived amine paired with Mosher’s acid was found to be an effective catalyst for this reaction. The methodology was applied to the first asymmetric synthesis of (2S,3S)-2-nor-epoxy-methylenomycin B, which exhibits strong antibacterial activity. In the last part of this thesis, the α-alkylation reaction of α-branched aldehydes via enamine catalysis is presented. A combination of a sterically hindered proline-derived amine and an acid in the presence of base was found to promote the reaction with excellent enantiocontrol for a wide variety of α-branched aryl-substituted aldehydes. The first α-benzylation reaction of α-branched aldehydes via enamine catalysis was realized by controlling the reaction environment using acid and base additives.
