Chapter 1 briefly covers the development and utility of allylboron reagents in organic synthesis. Transition models proposed for addition to carbonyl groups and imines are discussed and selected examples of the utility of these reagents to the synthesis of complex molecule covered. In chapter 2 the allylation and crotylation of ketones using allyl- and crotyltrifluoroborates and montmorillonite K-10 are described. The method is scalable and utilizes a reliable catalyst with high functional group tolerance. A conventional work-up is not required for further purification, since the boric acid by-product of the reagent remains trapped in the cavity of the K-10. The method is quite robust and provides an operationally straightforward procedure for the allylation of a range of ketones using the air and moisture stable potassium allyltrifluoroborate. In Chapter 3, the first indium-mediated highly chemo- and diastereoselective allylation of α,β- epoxyketones using allyltrifluoroborate was developed. It was shown in the case of simple ketone substrates, the loading of indium can be reduced to catalytic quantities without a diminishment in yield. The stereochemical nature of the epoxy homoallylic alcohols was ii unequivocally established through Payne rearrangement. Mechanistic studies indicate that the reaction proceeds through an allylindium species; although the nature of the indium species was not fully elucidated. Finally, in chapter 4 regioselective allylation and diastereoselective crotylation of various indoles are discussed using BF3·Et2O as a promoter. It was shown that the electronic effects of the substituents on the indole ring had little effect on the outcome of the reaction. However, steric factors were more influential on the yields and reactivity of the substrates. Stereospecific addition of the E- and Z-crotyltrifluoroborates could also be achieved under the reaction conditions, providing the corresponding anti and syn products, respectively.

Chapter 1 briefly covers the development and utility of allylboron reagents in organic synthesis. Transition models proposed for addition to carbonyl groups and imines are discussed and selected examples of the utility of these reagents to the synthesis of complex molecule covered. In chapter 2 the allylation and crotylation of ketones using allyl- and crotyltrifluoroborates and montmorillonite K-10 are described. The method is scalable and utilizes a reliable catalyst with high functional group tolerance. A conventional work-up is not required for further purification, since the boric acid by-product of the reagent remains trapped in the cavity of the K-10. The method is quite robust and provides an operationally straightforward procedure for the allylation of a range of ketones using the air and moisture stable potassium allyltrifluoroborate. In Chapter 3, the first indium-mediated highly chemo- and diastereoselective allylation of α,β- epoxyketones using allyltrifluoroborate was developed. It was shown in the case of simple ketone substrates, the loading of indium can be reduced to catalytic quantities without a diminishment in yield. The stereochemical nature of the epoxy homoallylic alcohols was ii unequivocally established through Payne rearrangement. Mechanistic studies indicate that the reaction proceeds through an allylindium species; although the nature of the indium species was not fully elucidated. Finally, in chapter 4 regioselective allylation and diastereoselective crotylation of various indoles are discussed using BF3·Et2O as a promoter. It was shown that the electronic effects of the substituents on the indole ring had little effect on the outcome of the reaction. However, steric factors were more influential on the yields and reactivity of the substrates. Stereospecific addition of the E- and Z-crotyltrifluoroborates could also be achieved under the reaction conditions, providing the corresponding anti and syn products, respectively.

The research presented herein is concerned with the exploration of the rhodium catalysed addition of organoboron reagents. Chapter 1 firstly introduces the area of organoboron reagents, focussing on the applications of potassium alkenyl trifluoroborate reagents. Secondly, an extensive discussion of the rhodium catalysed conjugate addition of organboron reagents demonstrates its utility as a key coupling step in recent syntheses. Chapter 2 describes synthetic methods towards alkenylboron reagents and describes the synthesis of functionalised and enantiopure alkenyl trifluoroborate salts. Chapter 3 discusses the rhodium catalysed addition of potassium alkenyl trifluoroborate salts to α,β-unsaturated compounds. A gas chromatography study addresses issues concerning protodeboronation and highlights the potential for olefin transposition. A new rhodium catalysed olefin transposition reaction has been thoroughly investigated and applied using the synthesised potassium alkenyl trifluoroborate salts. Chapter 4 describes the synthesis of biologically relevant, enantiopure dihydropyranones for use as acceptors in the rhodium catalysed conjugate addition reaction. The hetero-Diels-Alder reaction is employed to synthesise the dihydropyranones. Rhodium catalysed conjugate addition of arylboronic acids and potassium alkenyl trifluoroborates is utilised to concisely assemble late stage intermediates of natural products including diospongin B. Chapter 5 describes the synthesis and characterisation of the compounds discussed in chapters 2, 3 and 4.