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Catalytic Asymmetric Hydrogenation and Hydroboration Reactions
Abstract
The catalytic asymmetric hydrogenation (CAH) reaction is a preeminent tool for the generation of stereocenters. A large number of metal-ligand combinations have been developed to address specific challenges but limitations, especially with tetrasubstituted olefins, remain. The first portion of this dissertation focuses on the oxime-directed catalytic asymmetric hydrogenations of allylic oximes. The observation of an unexpected interaction in the catalytic cycle led to a series of new catalyst systems that efficiently reduce di-, tri- and tetrasubstituted olefins in less than one hour at one atm hydrogen pressure. Mechanistic probing provided evidence to support a new mechanism for which the activator-promoted asymmetric hydrogenations of oximes are thought to occur. The catalytic asymmetric hydroboration reaction is a cornerstone in asymmetric catalysis due to the wide variety of stereospecific transformations capable of the carbon–boron bond. A variety of regiodivergent, chiral boronates were prepared using the developed methodology included herein. Stereospecific conversion of these chiral products into boronic acids, borocycles, tertiary alcohols, and all-carbon quaternary compounds was illustrated. The new catalyst systems developed in the previous section were demonstrated to be efficient hydroboration catalysts as well.
Subject Area
Organic chemistry|Chemistry
Recommended Citation
Bochat, Andrew Jerome, "Catalytic Asymmetric Hydrogenation and Hydroboration Reactions" (2020). ETD collection for University of Nebraska-Lincoln. AAI28031664.
https://digitalcommons.unl.edu/dissertations/AAI28031664