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This thesis is concerned with the asymmetric synthesis of cyclopropyl derivatives via the use of chiral iron acyl complexes of the type (η⁵-C₅H₅)Fe(CO)(PPh₃)(COCH=CR'R), Chapter 1 reviews previous routes to optically active cyclopropyl derivatives and reviews the use of the chiral auxiliary (η⁵-C₅H₅)Fe(CO)(PPh₃) for asymmetric synthesis. Chapter 2 describes the synthesis of the complexes (η⁵-C₅H₅)Fe(CO)(PPh₃)(COCH=CRR') and presents a conformational analysis of the α, β-unsaturated acyl ligand. Chapter 3 describes the diastereoselective synthesis of cis- substituted cyclopropyl complexes via the reaction of Z-α, β-unsaturated iron acyl complexes with electrophilic alkylidene species. Decomplexation, to give the corresponding cyclopropyl esters, occurred without epimerisation of the cyclopropane ring. By the use of homochiral iron acyl complexes the enantioselective synthesis of cyclopropyl derivatives was achieved. Section A describes methylene addition and Section B isopropylidene addition reactions. Section C describes attempts to synthesise pyrethroid insecticide precursors which occurred with good diastereoselectivity but poor regioselectivity. Section D describes electrophilic ethylidene addition reactions in which the chiral auxiliary exerts good stereochemical control over three new chiral centres. Chapter 4 describes the diastereoselective synthesis of trans- substituted cyclopropyl complexes via the reaction of E-α, β-unsaturated iron acyl complexes with nucleophilic alkylidene transfer reagents. Section A describes methylene transfer reagents. Whilst α-lithiosulphides and α-lithiosulphoxides were of limited use, iodomethyllithium (generated in situ) resulted in highly diastereoselective syntheses of the cyclopropyl complexes. Decomplexation, to give the corresponding cyclopropyl esters, occurred without epimerisation of the cyclopropane ring. By the use of homochiral iron acyl complexes the enantioselective synthesis of cyclopropyl derivatives was achieved. Section B describes the generation of 1-iodoethyllithium and 1-iodobutyllithium and their reactions as nucleophilic alkylidene transfer reagents. The stereo- chemistry at two of the new chiral centres is controlled by the iron chiral auxiliary, whilst that at a third is controlled by a number of factors.

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This thesis presents the design and structure of a number of Schiff-base pyrrole macrocycles, their use in the formation of mono- and dinuclear calcium complexes, and reactions with various alkali- and transition metals to form mixed-metal clusters. Chapter One introduces the range of Schiff-base macrocycles with tuneable properties for various synthetic applications. Previously reported complexes of various s-, d- and f-block metals in these macrocyclic frameworks are also discussed. Research into calcium chemistry is reviewed, both in catalysis of synthetic organic processes, and in synthetic modelling of reaction clusters found in protein structures. Chapter Two details the synthesis of three monometallic calcium complexes utilising Schiff base macrocycles H4LEt and H4LA, and dipyrrin ligand HLD. Reactions of Ca(THF)2(H2LEt) with transition metal halides and amines is outlined, leading to the formation of M2(LEt) (M = Fe, Co, Cu). Deprotonation of Ca(THF)2(H2LEt) with alkali metal amines forms calcium-alkali metal complexes; further reactivity of these with transition metal halides demonstrates unusual stoichiometry in the synthesis of mixed-metal clusters. Some of these complexes were assessed for catalytic activity in the hydroamination of isocyanates. Chapter Three describes the synthesis and characterisation of bimetallic calcium complexes of the ligands H4LEt, H4LA and H4LS5. Reactions of Ca2(THF)2(μ- THF)(LEt) with a range of small molecules - including H2O, LiOH and KOH - is outlined. In particular, reactivity of Ca2(THF)2(μ-THF)(LEt) with NaOH yielded calcium-alkali metal clusters Ca2(THF)2(μ-OH)(Na{THF}2)(LEt) and Ca2(THF)2(μ- OH)2(Na{THF})2(LEt), which displayed alternate wedged and bowl-shaped conformations of the macrocycle ligand. Further homobimetallic complex syntheses of M2(LEt) (M = Sn, Mn, Sr) are also outlined for comparison to calcium complexes. Chapter Four presents a summary of the work presented in this thesis, and Chapter Five outlines the full experimental procedures and analytical data for all described complexes.

The aims of this project were to develop a cascade approach towards decahydroquinoline frameworks (Scheme I) and apply this to the synthesis of decahydroquinoline-containing natural products such as lycopodine, cermizine B and lepadin D (Scheme I). Scheme I. Several linear precursors were synthesized via a modular strategy. For example, lycopodine linear precursor i was synthesized in a total of 12 steps (Scheme II). Scheme II. Conditions for cyclization and hydrogenation were tested, with the diastereoselectivity examined in each system. For example, the lepadin linear precursor ii produced two decahydroquinolines iii and iv upon cyclization (Scheme III). Scheme III. It was found that the diastereoselectivity was dependent on the ring substituents and variation of the hydrogenation conditions could change the facial selectivity of enamine reduction.