Rhodium complexes bearing multidentate nitrogen donor ligands were investigated for their ability to promote alkyne and olefin functionalization reactions. This thesis work is comprised of two projects in which rhodium-heteroatom reactivity is investigated: P-H bond activation reactions and olefin functionalizations via rhodaoxetane intermediates. [Tp*Rh(PPh3)2] [Tp* = hydrotris(3,5-dimethylpyrazolyl)borate] and [Tp*Rh(cod)]2 (cod = cyclooctadiene) were evaluated for their activity in alkyne hydrophosphinylation in comparison to known catalysts for this reaction. [Tp*Rh(PPh3)2]and [Tp*Rh(cod)]2 were both shown to effect hydrophosphinylation of 1-octyne with diphenylphosphine oxide with high regioselectivity but moderate yields in comparison with Wilkinson's catalyst [C1Rh(PPh3)3]. [Tp*Rh(PPh3)2] was further shown to effect hydrophosphinylation of a range of aromatic and aliphatic alkynes with diphenylphosphine oxide, in each case exclusively providing the E-linear vinylphosphineoxide product. 1H and 31P NMR spectroscopy provided evidence that alkyne hydrophosphinylation in the presence of pyrazolylborate rhodium complexes follows an analogous mechanism to that proposed for this reaction catalyzed by [C1Rh(PPh3)3] or[C1Rh(cod)]2. The 2-rhodaoxetane [(TPA)Rhmec2_,-4u, 0-2-oxyethypr BPh4- (TPA = tris[(2-pyridal)methyl]amine) was investigated for its potential as an intermediate in proposed functionalization reactions of olefins. RTPA)Rh111(K2-C,0-2-oxyethyl)]+ BPh4- was prepared by two published methods with limited success. A third method involved the use of nitrous oxide to oxygenate [(12-ethene)(K4-TPA)Rh1]+ to RTPA)Rh1110(-2-C,0-2-oxyethyDr. Only a trace amount of [(TPA)Rhmoc2 -C,0-2-oxyethypr was observed in the 1I-1 NMR spectrum of this reaction mixture. Initial test reactions of [(TPA)Rhilioc2_C,0-2-oxyethypr combined with substrates (aniline, toluenesulfonamide, phenylboronic acid, or benzaldehyde) were inconclusive since the results were obscured by the impurity of the samples.

Thesis (doctoral)--Lund University, 1995. / Added t.p. with thesis statement inserted.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 110-113.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 166-178). Available also in a digital version from Dissertation Abstracts.

Thesis (doctoral)--Lund University, 1995. / Added t.p. with thesis statement inserted.

Rhodium complexes bearing multidentate nitrogen donor ligands were investigated for their ability to promote alkyne and olefin functionalization reactions. This thesis work is comprised of two projects in which rhodium-heteroatom reactivity is investigated: P-H bond activation reactions and olefin functionalizations via rhodaoxetane intermediates. [Tp*Rh(PPh3)2] [Tp* = hydrotris(3,5-dimethylpyrazolyl)borate] and [Tp*Rh(cod)]2 (cod = cyclooctadiene) were evaluated for their activity in alkyne hydrophosphinylation in comparison to known catalysts for this reaction. [Tp*Rh(PPh3)2]and [Tp*Rh(cod)]2 were both shown to effect hydrophosphinylation of 1-octyne with diphenylphosphine oxide with high regioselectivity but moderate yields in comparison with Wilkinson's catalyst [C1Rh(PPh3)3]. [Tp*Rh(PPh3)2] was further shown to effect hydrophosphinylation of a range of aromatic and aliphatic alkynes with diphenylphosphine oxide, in each case exclusively providing the E-linear vinylphosphineoxide product. 1H and 31P NMR spectroscopy provided evidence that alkyne hydrophosphinylation in the presence of pyrazolylborate rhodium complexes follows an analogous mechanism to that proposed for this reaction catalyzed by [C1Rh(PPh3)3] or[C1Rh(cod)]2. The 2-rhodaoxetane [(TPA)Rhmec2_,-4u, 0-2-oxyethypr BPh4- (TPA = tris[(2-pyridal)methyl]amine) was investigated for its potential as an intermediate in proposed functionalization reactions of olefins. RTPA)Rh111(K2-C,0-2-oxyethyl)]+ BPh4- was prepared by two published methods with limited success. A third method involved the use of nitrous oxide to oxygenate [(12-ethene)(K4-TPA)Rh1]+ to RTPA)Rh1110(-2-C,0-2-oxyethyDr. Only a trace amount of [(TPA)Rhmoc2 -C,0-2-oxyethypr was observed in the 1I-1 NMR spectrum of this reaction mixture. Initial test reactions of [(TPA)Rhilioc2_C,0-2-oxyethypr combined with substrates (aniline, toluenesulfonamide, phenylboronic acid, or benzaldehyde) were inconclusive since the results were obscured by the impurity of the samples. / Science, Faculty of / Chemistry, Department of / Graduate

No description available.

The enantioselective chlorination of alcohols by the menthyldipheny1-phosphine/carbon tetrachloride reagent previously reported in the literature was investigated and quantified. Further examples were found. A new enantioselective reaction of menthyldipheny1phosphine/carbon tetrachloride was discovered. This was the synthesis of aziridines by ring closure of ? amino alcohols. Other optically active phosphines in conjunction with carbon tetrachloride were found to react in a similar manner to menthy1dipheny1phosphine/carbon tetrachloride with a variety of ? amino alcohols. Menthy1dipheny1phosphine was found to react enantioselectively with a ? amino alcohol in the presence of chlorine.

Chapter 1 reviews the literature concerning trimethylenemethane and oxodimethylenemethane metal complexes and their r?le in organic synthesis. The preparation and characterisation of ?4-trimethylenemethane metal complexes of iridium, rhodium, osmium and ruthenium are presented in Chapter 2, together with the molecular structure of three of these complexes which establishes the presence of the ?4-trimethylenemethane ligand. The room temperature 1H n.m.r. spectra show the expected features for a static structure and no sign of rotation of the trimethylenemethane ligand was observed at higher temperatures. Preliminary investigation into the reactivity of these trimethylenemethane complexes is detailed in Chapter 3. A series of cationic ?4-trimethylenemethane complexes are prepared by the reaction of [Ir{?4-C(CH2)3}C1 (CO)(PPh3)] with silver hexafluorophosphate in the presence of a donor ligand such as carbon monoxide or ethene. The reactions of these cationic complexes with neutral and anionic nucleophiles are investigated and show that displacement of other donor ligands or attack on co-ordinated carbonyl and ethene ligands occurs, rather than attack at, or displacement of the trimethylenemethane ligand. Chapter 4 describes the reaction of 3-trimethylsilyl-2-(methyl- sulphonyloxymethyl) prop-l-ene with d10-metal complexes of platinum, palladium and nickel. The isolation of ?3-2-trimethylsilylmethylallyl palladium and platinum complexes are of interest since they are postulated intermediates implicated in the generation of the catalytic species [Pd (?3-trimethylenemethane) (PPh3)2]. The d10 -nickel complex [Ni{P(OEt)3}4] catalyses the cycloaddition of trimethylenemethane to electron-deficient alkenes and imines, the latter reaction affords a high yield synthesis of 4-methylenepyrrolidines. The final Chapter describes the reactions of 3-chloro-l-(trimethyl-silyl)propan-2-one and 3-chloro-2-(trimethylsiloxy)prop-l-ene with low-valent metal complexes to afford oxodimethylenemethane complexes of platinum, iridium, and osmium. The molecular structure of two of these complexes establishes the presence of an ?3-oxodimethylenemethane ligand. The silylenol ether, 3-chloro-2-(trimethylsiloxy)prop-l-ene was readily prepared from 3-chloro-l-(trimethylsilyl)propan-2-one, the isomerisation being catalysed by a number of low-valent metal complexes.

No description available.