Studies on organocatalytic ketone/nitroalkene Michael addition reactions

Kirby, Raie Lene (2012) Studies on organocatalytic ketone/nitroalkene Michael addition reactions. Masters thesis, Memorial University of Newfoundland.

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Abstract

The organocatalytic Michael addition of aldehydes to ketones is of continuing interest in development of organocatyists for asymmetric synthesis. The Pansare laboratory has focused on research surrounding organocatalysts developed to aid in fundamental carbon-carbon bond forming reactions including the Michael addition reaction. -- Due to the ability to generate up to three stereocenters and products that are useful synthetic intermediates, the organocatalytic Michael addition reaction continues to be of special interest. The work described in this thesis focuses on activation of the nucleophile (Michael donor) through enamine formation with a chiral amine. Simple pyrrolidine-based diamine catalysts showed moderate to high enantioselectivities (up to 92% ee) for conjugate Michael addition reactions of cyclic ketones to nitroalkenes without acid additive. Details regarding the effect of catalyst side chain p Ka on the stereoselectivity as well as the importance of secondary-secondary diamine motif and H-bond donor functionality in the organocatalyst for Michael addition reactions of cyclic ketones to nitroalkenes are discussed

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