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<p>Solvolysis reactions of a range of tertiary substrates in largely aqueous solvents were studied in such respects as β-deuterium kinetic isotope effects, linear free energy relationships and stereochemistry.</p><p>Solvolysis of the fluorene derivatives 9-methyl–9-(2´-X-2´-propyl)fluorene (<b>1-X,</b> X = Cl, Br, OOCCF₃) involves a very short-lived carbocation intermediate. The fraction of alkene is increased by addition of general bases, which can be expressed by a Brφnsted parameter β = 0.07. The kinetic deuterium isotope effects vary with solvent composition in a way which is not consistent with a common carbocation intermediate which has time to choose between dehydronation and addition of a solvent water molecule. </p><p>In the absence of bases, the reaction of 4-chloro-4-(4´-nitrophenyl)pentan-2-one (<b>2-Cl</b>) proceeds through a short-lived carbocation intermediate yielding 4-(4´-nitrophenyl)-2-oxopent-4-ene (<b>2-</b><b>t</b>-ne)as the main elimination product. Addition of acetate ion and other weak bases results in the base-promoted E2 (or E1cb) reaction to give (<i>E</i>)-4-(4´-nitrophenyl)-2-oxopent-3-ene (<b>2-</b><b>E</b>-ne) and (<i>Z</i>)-4-(4´-nitrophenyl)-2-oxopent-3-ene(<b>2-</b><b>Z</b>-ne). There is no evidence for a water-promoted E2 (or E1cb) reaction.</p><p>The stereochemistry studies of elimination from (<i>R,S</i> and <i>S,R</i>)-[1-(3´-fluoro)phenyl-2-methyl]cyclopentyl-<i>p-</i>nitrobenzoate (<b>3-PNB</b>) and its (<i>R</i>,<i>R</i> and <i>S,S</i>)isomer <b>3´-PNB</b> and (<i>R,S</i> and <i>S,R</i>)-[1´-(3´´-fluoro)phenyl-2´-methylcyclopentyl]-2,2,2-trifluoroacetate(<b>3-OOCCF</b><b>3</b>) exclude the concerted pericyclic elimination mechanism for formation of the alkene 1-(3´-fluoro)phenyl-2-methylcyclopentene(<b>3-</b><b>m</b>-ne). The effects of added thiocyanate ion and halide ions on the solvolysis reaction are discussed.</p><p>Mass spectrometry analysis showed complete incorporation of the labeled oxygen from solvent water into the product 2-hydroxy-2-phenyl-3-butene (<b>4-OH</b>), confirming that it is the tertiary carbon-oxygen bond that is broken in the acid-catalyzed solvolysis of 2-methoxy-2-phenyl-3-butene (<b>4-OMe</b>). The mechanism for the dominant formation of the less stable <b>4-OH</b> is discussed.</p>

<p>The Ru(arene)[(1<i>S</i>, 3<i>R</i>, 4<i>R</i>)-3-(Hydroxymethyl)-2-azabicyclo[2.2.1]heptane catalyst was optimized as ligand in the asymmetric transfer hydrogenation of ketones and resulted in increased activity and enantioselectivity of the catalyst. Dioxolane substitution at the rear end of the amino alcohol ligand and introduction of a (<i>R</i>)-methyl substituent yielded a catalyst that reduced acetophenone in 96% enantiomeric excess in 90 minutes with a substrate to catalyst molar ratio of 5000. A diversity of substituted aromatic ketones was reduced with excellent rate and enantioselectivity. Based on experimental and computational results, a study of the origin of the enantioselectivity was conducted. A combination of electrostatic, steric, dispersion forces and solvation effects was suggested to be the cause of the stereo discrimination. A set of amino sulfides built upon the 2-azabicyclo and the cyclohexane structures were prepared and tested as ligands in the enantioselective transfer hydrogenation of acetophenone with [IrCl(COD)]₂ as metal precursor. With this type of catalysts, the reaction rates were good but the enantioselectivity unsatisfactory with 70% as the highest obtained enantiomeric excess. The first enantioselective reduction of aromatic 2<i>H</i>-azirines was accomplished by using the asymmetric transfer hydrogenation protocol. Aromatic azirines were reduced to yield chiral aziridines with up to 72% enantiomeric excess and good yields. The enantioselectivity and reactivity of the reaction were strongly influenced by substituents on the aromatic and aliphatic moiety of the substrate.</p>

<p>[¹¹C]Carbon monoxide in low concentrations has been used in palladium- or seleniummediated carbonylation reactions such as the synthesis of ¹¹C-imides, hydrazides, amides, carboxylic acids, esters, carbothioates, ketones and carbamoyl compounds.</p><p>In these reactions aryl iodides have been used in most cases. However, less reactive aryl triflate, chloride and bromides were activated using tetrabutylammonium iodide.</p><p>The reactivities of nucleophiles may have influence on the radiochemical yield of the ¹¹Clabelled compounds. Carboxyamination of aryl halides using aniline derivatives yielded 10% of the corresponding ¹¹C-amide. However, the radiochemical yields increased significantly when the aniline derivatives were treated with lithium bis(trimethylsilyl)amide. In contrast, this reagent did not improve the radiochemical yields when primary amines such as methylamine and benzylamine were used. In these cases the radiochemical yields were improved by using pempidine.</p><p>¹¹C-Esterification usually gave low yields. However, the radiochemical yields of ¹¹C-esters could be improved by using magnesium bromide and pempidine.</p><p>An excess of ligand may have a significant impact on palladium-promoted carbonylation reaction. The radiochemical yields of ¹¹C-ketones were improved when using excess amounts of tri-o-tolylphosphine.</p><p>(¹³C)Carbon monoxide may be utilized for the synthesis of ¹³C-substituated compounds in order to confirm the position of ¹¹C-labelling.</p>

<p>This thesis describes free-radical reactions for the construction of tetrahydrofuran and pyrrolidine derivatives. The studies are concerned with (<i>i</i>) diastereoselectivity in radical cyclisation, (<i>ii</i>) construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones <i>via</i> radical carbonylation/cyclisation and (<i>iii</i>) synthesis of tetrahydrofuran derivatives <i>via</i> group-transfer cyclisation of organochalcogen compounds.</p><p>(<i>i</i>) Diastereoselectivity in the synthesis of tetrahydrofuran derivatives <i>via</i> radical cyclisation was controlled by addition of Lewis acids. In the synthesis of 2,4-disubstitued tetrahydrofurans, the <i>trans</i>-isomer was formed as the major product in the unperturbed reaction. Upon addition of trialkylalumiums the diastereoselectivity was reversed. In a similar fashion, <i>exo</i>/<i>endo</i>-diastereoselectivity in the synthesis of bicyclic 2,3,4-trisubstituted tetrahydrofurans could also be controlled.</p><p>(<i>ii</i>) Procedures for construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones were presented. Epoxides were ring-opened with benzeneselenolate or benzenetellurolate and the resulting <i>β</i>-hydroxyalkyl phenyl chalcogenides were vinylated using ethyl propiolate/NMM or <i>E</i>-1,2-bis(phenylsulfonyl)ethylene/NaH. The corresponding nitrogen analogues were accessed by <i>N</i>-vinylation of aziridines followed by benzeneselenolate ring-opening. The two types of organochalcogen radical precursors were then treated with TTMSS/AIBN under an atmosphere of carbon monoxide (80 atm) to afford tetrahydrofuran-3-ones and pyrrolidin-3-ones, respectively, in high yields.</p><p>(<i>iii) </i>Microwaves were found to induce group-transfer cyclisation of <i>β</i>-allyloxyalkyl aryl chalcogenides. Short time heating (3-10 min) at 250 ^oC in ethylene glycol was required to obtain tetrahydrofuran derivatives in 60-91% yield.</p>

Solvolysis reactions of a range of tertiary substrates in largely aqueous solvents were studied in such respects as β-deuterium kinetic isotope effects, linear free energy relationships and stereochemistry. Solvolysis of the fluorene derivatives 9-methyl–9-(2´-X-2´-propyl)fluorene (<b>1-X,</b> X = Cl, Br, OOCCF3) involves a very short-lived carbocation intermediate. The fraction of alkene is increased by addition of general bases, which can be expressed by a Brφnsted parameter β = 0.07. The kinetic deuterium isotope effects vary with solvent composition in a way which is not consistent with a common carbocation intermediate which has time to choose between dehydronation and addition of a solvent water molecule. In the absence of bases, the reaction of 4-chloro-4-(4´-nitrophenyl)pentan-2-one (<b>2-Cl</b>) proceeds through a short-lived carbocation intermediate yielding 4-(4´-nitrophenyl)-2-oxopent-4-ene (<b>2-</b><b>t</b>-ne)as the main elimination product. Addition of acetate ion and other weak bases results in the base-promoted E2 (or E1cb) reaction to give (E)-4-(4´-nitrophenyl)-2-oxopent-3-ene (<b>2-</b><b>E</b>-ne) and (Z)-4-(4´-nitrophenyl)-2-oxopent-3-ene(<b>2-</b><b>Z</b>-ne). There is no evidence for a water-promoted E2 (or E1cb) reaction. The stereochemistry studies of elimination from (R,S and S,R)-[1-(3´-fluoro)phenyl-2-methyl]cyclopentyl-p-nitrobenzoate (<b>3-PNB</b>) and its (R,R and S,S)isomer <b>3´-PNB</b> and (R,S and S,R)-[1´-(3´´-fluoro)phenyl-2´-methylcyclopentyl]-2,2,2-trifluoroacetate(<b>3-OOCCF</b><b>3</b>) exclude the concerted pericyclic elimination mechanism for formation of the alkene 1-(3´-fluoro)phenyl-2-methylcyclopentene(<b>3-</b><b>m</b>-ne). The effects of added thiocyanate ion and halide ions on the solvolysis reaction are discussed. Mass spectrometry analysis showed complete incorporation of the labeled oxygen from solvent water into the product 2-hydroxy-2-phenyl-3-butene (<b>4-OH</b>), confirming that it is the tertiary carbon-oxygen bond that is broken in the acid-catalyzed solvolysis of 2-methoxy-2-phenyl-3-butene (<b>4-OMe</b>). The mechanism for the dominant formation of the less stable <b>4-OH</b> is discussed.

The Ru(arene)[(1S, 3R, 4R)-3-(Hydroxymethyl)-2-azabicyclo[2.2.1]heptane catalyst was optimized as ligand in the asymmetric transfer hydrogenation of ketones and resulted in increased activity and enantioselectivity of the catalyst. Dioxolane substitution at the rear end of the amino alcohol ligand and introduction of a (R)-methyl substituent yielded a catalyst that reduced acetophenone in 96% enantiomeric excess in 90 minutes with a substrate to catalyst molar ratio of 5000. A diversity of substituted aromatic ketones was reduced with excellent rate and enantioselectivity. Based on experimental and computational results, a study of the origin of the enantioselectivity was conducted. A combination of electrostatic, steric, dispersion forces and solvation effects was suggested to be the cause of the stereo discrimination. A set of amino sulfides built upon the 2-azabicyclo and the cyclohexane structures were prepared and tested as ligands in the enantioselective transfer hydrogenation of acetophenone with [IrCl(COD)]2 as metal precursor. With this type of catalysts, the reaction rates were good but the enantioselectivity unsatisfactory with 70% as the highest obtained enantiomeric excess. The first enantioselective reduction of aromatic 2H-azirines was accomplished by using the asymmetric transfer hydrogenation protocol. Aromatic azirines were reduced to yield chiral aziridines with up to 72% enantiomeric excess and good yields. The enantioselectivity and reactivity of the reaction were strongly influenced by substituents on the aromatic and aliphatic moiety of the substrate.

[11C]Carbon monoxide in low concentrations has been used in palladium- or seleniummediated carbonylation reactions such as the synthesis of 11C-imides, hydrazides, amides, carboxylic acids, esters, carbothioates, ketones and carbamoyl compounds. In these reactions aryl iodides have been used in most cases. However, less reactive aryl triflate, chloride and bromides were activated using tetrabutylammonium iodide. The reactivities of nucleophiles may have influence on the radiochemical yield of the 11Clabelled compounds. Carboxyamination of aryl halides using aniline derivatives yielded 10% of the corresponding 11C-amide. However, the radiochemical yields increased significantly when the aniline derivatives were treated with lithium bis(trimethylsilyl)amide. In contrast, this reagent did not improve the radiochemical yields when primary amines such as methylamine and benzylamine were used. In these cases the radiochemical yields were improved by using pempidine. 11C-Esterification usually gave low yields. However, the radiochemical yields of 11C-esters could be improved by using magnesium bromide and pempidine. An excess of ligand may have a significant impact on palladium-promoted carbonylation reaction. The radiochemical yields of 11C-ketones were improved when using excess amounts of tri-o-tolylphosphine. (13C)Carbon monoxide may be utilized for the synthesis of 13C-substituated compounds in order to confirm the position of 11C-labelling.

This thesis describes free-radical reactions for the construction of tetrahydrofuran and pyrrolidine derivatives. The studies are concerned with (i) diastereoselectivity in radical cyclisation, (ii) construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones via radical carbonylation/cyclisation and (iii) synthesis of tetrahydrofuran derivatives via group-transfer cyclisation of organochalcogen compounds. (i) Diastereoselectivity in the synthesis of tetrahydrofuran derivatives via radical cyclisation was controlled by addition of Lewis acids. In the synthesis of 2,4-disubstitued tetrahydrofurans, the trans-isomer was formed as the major product in the unperturbed reaction. Upon addition of trialkylalumiums the diastereoselectivity was reversed. In a similar fashion, exo/endo-diastereoselectivity in the synthesis of bicyclic 2,3,4-trisubstituted tetrahydrofurans could also be controlled. (ii) Procedures for construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones were presented. Epoxides were ring-opened with benzeneselenolate or benzenetellurolate and the resulting β-hydroxyalkyl phenyl chalcogenides were vinylated using ethyl propiolate/NMM or E-1,2-bis(phenylsulfonyl)ethylene/NaH. The corresponding nitrogen analogues were accessed by N-vinylation of aziridines followed by benzeneselenolate ring-opening. The two types of organochalcogen radical precursors were then treated with TTMSS/AIBN under an atmosphere of carbon monoxide (80 atm) to afford tetrahydrofuran-3-ones and pyrrolidin-3-ones, respectively, in high yields. (iii) Microwaves were found to induce group-transfer cyclisation of β-allyloxyalkyl aryl chalcogenides. Short time heating (3-10 min) at 250 oC in ethylene glycol was required to obtain tetrahydrofuran derivatives in 60-91% yield.

This thesis describes synthesis and radiohalogenation of closo-carborane and nido-carborate derivatives for application in nuclide therapy and imaging. The work could be divided in to four sections. In the first section, the synthesis of three boronated DNA-intercalators – 1–(N-9-acridinyl-3-aminopropyl)-para-carborane-12-carboxylic acid hydrogen chloride, 1-[1-(N-9-acridinyl-3-aminopropyl)-para-carborane 12-(3-propyloxi)]-1,3-propanediol, 1-(N-9-acridinyl-3-amino-propyl)-1-ortho-carborane-2-ylmethoxy)1-3-propandiol – for potential use in BNCT, using targeted delivery is described. The second section describes the application of the Heck-reaction to 2-iodo-para-carborane, which has successfully been reacted with a number of styrene derivatives, i.e. para-phenyl, chloro, bromo, nitro, methoxy, and methyl-styrene, to furnish the desired trans-β-2-B-para-carborane)styrene. In the third section, radio-iodination and radio-bromination of closo-carboranes is described. Reaction of the corresponding iodinated carborane, in the presence of palladium catalyst, [125I]iodinated and [76Br]brominated carboranes were obtained in high to excellent yields. Section four describes a method for indirect radiolabelling of antibodies with 76Br. It was shown that NBI, a isothiocyanatobenzene derivative of dodecahydro-7,8-dicarba-nido-undecaborate anion, could be radio-brominated using oxidative conditions. The radio-brominated NBI was thereafter conjugated to anti-HER2 antibody for biological evaluation.