For many years silicon tethers have been used to increase yields and control the stereochemical and regiochemical outcomes of coupling reactions. Silicon tethers may be incorporated into a wide range of reaction types including alkene metathesis, cycloadditions, and glycosylations. This thesis focuses on the development of the use of silicon tethers in oxidative coupling reactions. This is accomplished through the use of silyl bis-enol ether intermediates that are used for the stereocontrolled coupling of ketones. Normally two equivalents of a metal oxidant are needed to perform this reaction; however the work herein uses photochemical and electrochemical means to drive the reaction forwards. A different mode of reactivity of silyl bis- enol ethers is also explored through the use of energy transfer catalysis. This enables the [2+2] cycloadditon of silyl bis-enol ether intermediates for the formation of cyclobutane diols, and 1,4- diketones after oxidative cleavage. Together with traditional oxidative coupling, these two methods create stereodivergent approaches for the convergent synthesis of 1,4-diketones, so that either diasteromer can be accessed depending of the reaction conditions.Oxidative coupling was also used in a methodology for the synthesis of axially chiral biaryl compounds. After oxidative coupling of two cyclohexenones, aromatization will induce central to axial chirality exchange for the synthesis of biaryl ring systems as a single atropisomer. Unfortunately, however, unexpected rotation led to poor stereochemical outcomes of the biaryl products. In a similar reaction silyl enol ethers were oxidized to aces umpolung chemistry for the functionalization of ketones with pyrazoles and triazoles.

Creator

• Caravana, Aidan

DOI

• https://doi.org/10.21985/n2-p31j-4q62

Subject

• Organic chemistry

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:16637
• etdadmin_upload_996558

Date created

• 2023-01-01

Resource type

• Dissertation

Rights statement

• In Copyright