Chapter 1: Introduction A brief introduction to TRIR spectroscopy and its application to the study of reactive intermediates of organometallic complexes are provided. Chapter 2: The Photochemistry of Group VII NHC and Phosphine Complexes An introduction to the photochemistry of organometallic N-heterocyclic carbene complexes of the Group VII metals Mn and Re and a comparison with the analogous phosphine complexes is described. The photochemistry of the complexes has been studied using fast time resolved infrared spectroscopy (ns to IlS timescales). This Chapter explains the stability of metal-NHC bonds compared with metal-phosphine. The nature and reactivity of the intermediates of these complexes with alkanes in the presence of CO has been explained by analyzing a range of sterically different NHC complexes. Their rate constants have been determined in different alkane solvents to compare the reactivity of the phosphine and carbene complexes towards different alkanes. Evidence for the formation of agostic complexes is given. Chapter 3: Photochemical and Photophysical Investigation of fac-[Re(L)(COh( u- diimine)]" Complexes (where L = PPh3 or NHC) Rel( c-diimine) carbonyl complexes have great potential to act as infrared probes of DNA. The photophysics and photochemistry of fac-[Re(NHC)(CO))(a-diimine)t III complexes have been investigated by ps- and ns- TRIR spectroscopy. A comparison between both NHC and phosphine substituted Re(a-diimine) complexes is carried out. Moreover, the nature of the solvent and the substituent at the a-diimine has also been altered to study their effects on the energy of the excited states by emission and ns- and ps- TRIR spectroscopies. The 3MLCT excited state is found to be the lowest in energy in the fac-[Re(Iipr2Me2)(CO)3(dppz-F2)t complexes whilst the 3IL remains dominant for the other fac-[Re(Iipr2Me2)(CO)3(dppz)t complexes studied. A theoretical investigation using TD-DFT calculations into these complexes has been performed. Chapter 4: Investigation into the Photochemistry M«CF3hbpy)(COhX (M = Mn, Re and X = Br, Cl) This chapter focuses on the study of isomerization in M«CF3)2bpy)(CO)3X (M = Mn, Re and X = Br, Cl). The mer to fac isomerisation of Mn«CF3)2bpy)(CO)3Br in CH2Cb is investigated at room temperature using FTIR spectroscopy. The use of liquid CO2 at low temperature increases the life time of the intermediate and allows for the characterisation of a CO2-bound dicarbonyl species to be made. For the analogous Re complex, fac-Re«CF3)2bpy)(CO)3Cl, experiments were performed at low temperature in liquid CO2 and liquid CH2F2. Again,fac to mer isomerisation is observed.

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My thesis is composed of four themed sections: (1) The introduction reviews the Prins reaction, focusing mainly on the Prins condensation-cyclisation of homoallylic alcohols with aldehydes giving substituted tetrahydropyrans. This section also briefly reviews the Prins reaction giving dihydropyrans and the aza-Prins reaction giving piperidines and dihydropiperidines. (2) The results and discussion section details the author's own work and is further divided into two parts. The first part describes the synthesis of novel homoallylic alcohols and bis-homoallylic alcohols from Pd(O)/ln(O) mediated three and five component cascade reactions respectively. The reaction is shown to be catalytic in both Pd(O) and In(O) and the efficiency of the 2,2'-bithiophene as additive is clearly demonstrated and explained. The reaction conditions have been optimised and include a safer and environmentally friendly solvent, a reduction in reaction time (from 16 to 2h) and an increase in reaction yield (from 40-42 to 59- 94%). The software package Spartan" is employed to predict likely conformations of the products. The second part describes the synthesis of 2,4,4,6-substituted tetrahydropyrans using statistically optimised Prins reaction conditions. Excellent control of stereoselectivity at C(4) of the tetrahydropyran is achieved through solvent choice, which allows either epimer to be accessed, with solvent polarizability the key factor. (3) The robotics and statistical techniques section details the statistical techniques Principal Component Analysis (PCA) and Design of Experiments (DoE), the author's own robotic system setup and the unique design of a new reaction vessel for three-phase (solid, liquid, and gas) reaction systems. The second part details the design, robotic setup and statistical analysis of the authors output. (4) The thesis concludes with full experimental details of the authors own work, together with the appropriate physical, spectroscopic and analytical data for all new compounds.

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This Thesis is divided into three parts: Introduction (Chapter 1), Result and Discussion (Chapter 2) and Experimental (Chapter 3). The Introduction (Chapter 1) provides a review of the recent literature relating to the 1,3dipolar cycloaddition reactions. It· covers nitrones, azomethine ylides and azomethine imines. The Result and Discussion. section (Chapter 2) deals with the author's work which is . concerned with developing four novel multicomponent cascade reactions. These are (i) a 3- component cascade involving bifunctional aryl halide! Michael acceptors, allene and arriine or sulphonamide nucleophiles (ii) a 3-component cascade involving bifunctional arylhalide! Michael acceptors, carbon monoxide and primary ~nes (iii) a 4-component cascade involving a bifunctional aryliodide! aldehyde, hydrazines, allene and· a dipolarophile and (iv) a 3-component cascade involving 2-bromomethyl iodobenzene, carbon monoxide and / ' hydrazines. { Cascade (i) and (ii) employ a common bifunctional Michael acceptor! arylhalide and a series of these were prepared all of which had an a, .p- unsaturated amide as the Michael acceptor. In·niost caSe these contained a chiral amide function while enabled the author to study chiral induction and diastereomer product ratios. In series (i) product yields ranged from 54-75% but there was essentially no chiral induction (dr's 1:1-1:1.6). Series (ii) gave a range of interesting isoindolones in 61-78% yield but again there was no significant chiral induction (dr 1:1-1:1.7). In both series we concluded the chiral amide centre is too distant from the site of the newly created chiral centre to have a controlling influence. Series (iii), the 4-component cascade proceeded regia-and stereoselectively in 55-72% yield. The IH NMR spectra of the pyrazolidine products showed line broadening due to N-Ione pair inversion processes which was confirmed by variable temperature IH NMR studies. An approximate inversion barrier of 12-15 Kcals.morl wa~ estimated. The final series, series (iv), was only briefly studi~d with two examples completed in 61-64% yield. .The thesis concludes (Chapter 3) with full experimental details' of all new compounds together with their appropriate physical, spectroscopic and analytical data.

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This thesis describes the investigation of the effect of hydrogen bonding on the rate of phosphoryl transfer in the reaction of diethyl 8-dimethylamino-I-naphthyl phosphate 3 with a nucleophile. The study of the hydrolysis of triester 3 is in the literature; triester 3 is catalysed by the dimethylammonium general acid, with a rate acceleration of almost 106 in comparison to the hydrolysis of diethyl I-naphthyl phosphate. 58 To ascertain whether the reactivity of triester 3 is specific to this system, the methylation of the amine in triester 3 was altered. Triesters diethyl 8- amino-I-naphthyl phosphate 6 and diethyl 8-methyIamino-l-naphthyl phosphate 7 were synthesised and their reaction with water and hydroxylamine was studied. It is concluded that the effect of methylation of the amine on the rate of P-O cleavage in triester 3 is insignificant, and that the hydrogen bond donor ability of the amino proton donor is not an important factor in increasing the rate of P-O cleavage; the energy of triesters 6H+, 7H+ and 3H+ are very similar. The hydrolysis of 8-dimethylamino-l-naphthyl phosphate 5m is also known to exhibit general acid catalysis by the dimethylammonium group." To ascertain whether the effect of methylation of the amine on the rate of p-o cleavage in monoester 5mis also insignificant, the hydrolysis of 8- rnethylamino-I-naphthyl phosphate 27m was studied. It is concluded that methylation of the amino general acid in triester 6H+ and monoester 5m has no significant effect on the rate of phosphoryl transfer, regardless of the different transition states that are formed. By studying the hydrolysis of monoester 36d it is concluded that the reactivity of monoester 5m is also dependent on the proton donor ability of the amino group. The elimination of various functionalised 8-amino-I-tetralone-3-sulfonic acids with hydroxide has been studied. There is a clear difference between the rates of elimination of the tetralones upon varying the proton donor ability of the amino group. No apparent trend relating the rate of elimination to the proton donor ability of the hydrogen bond donor, or to the pKa of the conjugate acid of the tetralones is observed.

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