Date of Award

5-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Chemical Engineering

First Advisor

Norito Takenaka

Second Advisor

Yi Liao

Third Advisor

Nasri Nesnas

Fourth Advisor

James R. Brenner

Abstract

The chiral hydrazine is a crucial structural motif that serves as pivotal structural elements in numerous natural products and biologically significant molecules. We are particularly interested in the catalytic asymmetric reduction of hydrazones, as well as the catalytic asymmetric propargylation and allenylation of hydrazones, because they provide direct pathways to these enantio-enriched chiral building blocks. In this work, we will explore the potential of two different categories of chiral Lewis base catalysts in the said transformations.

Developed by another student in our group, axial-chiral 3,3’-triazolyl biisoquinoline N,N’-dioxides derived catalysts are tested and demonstrated its capability in activating various hydrazone substrates in asymmetric hydrosilylation reactions. Another catalyst evaluated is a helicene-based 2,2’-bipyridine N-monoxide. It has shown great potential in asymmetrically catalyzing the propargylation of acylhydrazones with allenyltrichlorosilane, as well as in the allenylation of acylhydrazones with propargyltrichlorosilane. It showcased its capability of inducing enantioselectivity while maintaining great regiospecificity under an optimized catalytic system.

These classes of catalysts have been found to complement each other quite well. Their modular synthesis approach also facilitated the creation of diverse catalyst variants with different steric and electronic properties.

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