I. Magnesium Promoted Coupling of Carbodiimides and Terminal Acetylenes, II. Bismuth Compounds Supported by Di(amido) Chelating Ligands

<p>The work presented in this thesis is divided into two parts, both of which investigate the chemistry of main group elements supported by N,N'-donor ligands. Part 1 investigates the use of Mg(mesC{NCy}₂)(N{SiMe₃}₂)(THF) (mes = 2,4,6- Me₃C₆H₃, Cy = C₆H₁₁) as a pre-catalyst for the coupling of terminal acetylenes to carbodiimides. A catalytic cycle for the reaction is proposed, based on a series of stoichiometric reactions. Ligand redistribution via Schlenk equilibria is a prominent feature of the proposed catalytic cycle. The scope of catalysis was also investigated, indicating a strong dependence on the sterics and electronics of both the carbodiimide and the terminal acetylene. Investigation of other magnesium species identified other pathways into the catalytic cycle. Part 2 explores the derivitisation of Bi(Me₂Si{NAr})Cl (Ar = 2,6-i-Pr₂C₆H₃) to form a number of novel bismuth(III) species of the general formula Bi(Me₂Si{NAr})X (X = alkyl, aryl, amide, aryloxide, phosphide). In addition, a number of cationic bismuth species have been isolated from the reaction of Bi(Me₂Si{NAr})Cl with ECl₃ (E = Al, Ga). Preliminary investigations reveal that the amide and aryloxide derivatives are active as initiators for the ring-opening polymerisation of lactide and ε-caprolactone. A number of bismuth(III) compounds bearing the related di(amido)ether ligands [O(Me₂Si{NAr})₂]²⁻ have also been synthesised.</p>

I. Magnesium Promoted Coupling of Carbodiimides and Terminal Acetylenes, II. Bismuth Compounds Supported by Di(amido) Chelating Ligands

<p>The work presented in this thesis is divided into two parts, both of which investigate the chemistry of main group elements supported by N,N'-donor ligands. Part 1 investigates the use of Mg(mesC{NCy}₂)(N{SiMe₃}₂)(THF) (mes = 2,4,6- Me₃C₆H₃, Cy = C₆H₁₁) as a pre-catalyst for the coupling of terminal acetylenes to carbodiimides. A catalytic cycle for the reaction is proposed, based on a series of stoichiometric reactions. Ligand redistribution via Schlenk equilibria is a prominent feature of the proposed catalytic cycle. The scope of catalysis was also investigated, indicating a strong dependence on the sterics and electronics of both the carbodiimide and the terminal acetylene. Investigation of other magnesium species identified other pathways into the catalytic cycle. Part 2 explores the derivitisation of Bi(Me₂Si{NAr})Cl (Ar = 2,6-i-Pr₂C₆H₃) to form a number of novel bismuth(III) species of the general formula Bi(Me₂Si{NAr})X (X = alkyl, aryl, amide, aryloxide, phosphide). In addition, a number of cationic bismuth species have been isolated from the reaction of Bi(Me₂Si{NAr})Cl with ECl₃ (E = Al, Ga). Preliminary investigations reveal that the amide and aryloxide derivatives are active as initiators for the ring-opening polymerisation of lactide and ε-caprolactone. A number of bismuth(III) compounds bearing the related di(amido)ether ligands [O(Me₂Si{NAr})₂]²⁻ have also been synthesised.</p>

SYNTHESIS OF 1,2,3-TRIAZOLO-QUINOLIZIDINES BASED ON THE QUINOLIZIDINE ALKALOID LUPININE

The modification of the quinolysin alkaloid lupinine was carried out with the intro-duction of 1,2,3-triazolyl substituents for the hydroxymethylene group in the C-1 position of the quinolysin backbone. The reaction of lupinine with methanesulfochloride in the presence of triethylamine smoothly led to lupinine methanesulfonate, whose further reaction with sodium azide in DMFA led to lupinilazide. 1,3-Dipolar [4+2]-cycloaddition of the resulting azide to alkynes produced more stable 1,2,3-triazole compounds. The interaction of lupinilazide with 2-ethinylpyridine and with alcohols containing a terminal acetylene group (propargyl alcohol, 2-methylbut-3-in -2-ol or hex-5-in -1-ol) proceeded smoothly in the DMFA medium. The reactions were carried out in the presence of an aqueous solution of CuSO4 and sodium ascorbate in DMFA and allowed the corresponding 4-substituted (1S,9aR)-1H-1,2,3-triazol-1-yl to be synthesized with good yields)methyl)octahydro-1H-quinolysins. The results of studying the structural features of synthesized compounds by 1H - and 13C - NMR spectroscopy, as well as data from the two-dimensional COSY (1H-1H) and HMQC (1H-13C) spectra are presented. The values of chemical shifts, multiplicity and integral intensity of 1H and 13C signals in one-dimensional NMR spectra are determined. In the spectra of all synthesized new quinolizi-dinotriazoles, there is a peak of the fragmentary C10H17N ion (150-151 cu), corresponding to the cleavage of the molecule by the C-10 atom of the quinolizidine backbone.

Synthesis of quinolines through copper-catalyzed intermolecular cyclization reaction from anilines and terminal acetylene esters

A simple and convenient copper-catalyzed intermolecular cyclization reaction for the synthesis of quinolines from anilines and terminal acetylene esters has been developed.