Transition Metal Catalysis for Novel Syntheses and Applications of Arylboronic Acids and their Derivatives

Abstract

The research investigations presented herein are concerned with the syntheses and applications ofarylboronic acids and their derivatives; with a particular focus on their accessibility or utility incertain of the most significant modern transition metal-catalysed reactions to involveorganoborons.Chapter 1 provides an introduction to the field of organoboron chemistry, from its rootsemploying borane and related highly reactive derivatives for uncatalysed hydroboration of olefinsand acetylenes, to the modern classes of organoboron reagents of the greatest significance to therelated contemporary transition metal-catalysed methodologies. Furthermore particular emphasisis placed on the discussion of arylboronic acids, their synthesis, and application to transitionmetal catalysis as a result of their propensity to undergo useful transmetallation events.Chapter 2 details the use of a commercially available sulfonated monophosphine ligand in therhodium-catalysed 1,2-addition reaction employing aryl aldehydes and arylboronic acids inaqueous media. The high and continued activity of the catalytic complex is demonstrated by itbeing successfully recycled five consecutive times in the arylation reaction of an aryl aldehyde; aswell as being active for the arylations of more sterically demanding aryl methyl ketone substrates.Chapter 3 details the design and synthesis of a novel bench-stable azidomethylene substitutedarylboronate ester. The reactivity of this compound and a related analogue in both the coppercatalysedazide alkyne cycloaddition reaction and the Suzuki coupling reaction are detailed,culminating in the proof-of-concept use of such versatile synthetic building blocks in thesynthesis of a drug-substance derivative.Chapter 4 details alternative synthetic approaches to that used in Chapter 3 in order to accessbifunctional azidomethylene substituted arylboronate esters. In particular the application ofMiyaura borylation of arylhalides bearing benzylic azides is addressed as a means to rapidlyaccess substrates which are otherwise shown to be incompatible with classical s-block syntheticintermediates.

Date of Award	31 Dec 2012
Original language	English
Awarding Institution	University of Bath
Supervisor	Christopher Frost (Supervisor) & Gareth Price (Supervisor)