{"id":{"repo_id":"whiterose","oai_identifier":"oai:etheses.whiterose.ac.uk:1218"},"canonical_url":"https://search.dev.ndltd.org/etd/whiterose/oai:etheses.whiterose.ac.uk:1218","repository":{"repo_id":"whiterose","name":"White Rose University Consortium","base_url":"https://etheses.whiterose.ac.uk/cgi/oai2"},"display":{"title":"Synthesis of P-Stereogenic Bisphosphine Ligands: Application as Hemi-labile Ligands in the Asymmetric Pauson-Khand Reaction","abstract":"The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone. The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone.","abstract_html":"The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone. The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone.","abstract_has_math":false,"creators":["Haji-Cheteh, Chehasnah"],"institution":"University of York","degree_name":"M.Sc by research","degree_level":"masters","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["O'Brien, Peter","Fairlamb, Ian"],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010","date_published":"2010","updated_at":"2026-07-24T06:04:19Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["O'Brien, Peter","Fairlamb, Ian"]},{"key":"dc:creator","label":"Author","values":["Haji-Cheteh, Chehasnah"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2010"]},{"key":"dc:date.issued","label":"Date","values":["2010"]},{"key":"dc:publisher.commercial","label":"Dc Publisher Commercial","values":["University of York"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Chemistry (York)"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of York"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://etheses.whiterose.ac.uk/id/eprint/1218/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["M.Sc by research"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://etheses.whiterose.ac.uk/id/eprint/1218/1/chehasnah_thesis_edited_2010.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone. The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone."]},{"key":"dc:format","label":"Dc Format","values":["text"]},{"key":"dc:title","label":"Title","values":["Synthesis of P-Stereogenic Bisphosphine Ligands: Application as Hemi-labile Ligands in the Asymmetric Pauson-Khand Reaction"]}]}],"canonical_facts":{"dc:contributor.advisor":["O'Brien, Peter","Fairlamb, Ian"],"dc:creator":["Haji-Cheteh, Chehasnah"],"dc:date":["2010"],"dc:date.issued":["2010"],"dc:description.abstract":["The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone. The synthesis of new P-stereogenic ligands and investigation of their use in a Co-catalysed asymmetric Pauson-Khand reaction has been carried out. The ligands were synthesised by asymmetric lithiation of a phosphine sulfide or a phosphine borane using alkyllithium/()-sparteine complexes, trapping with Ph2PCl or t-Bu2PCl and treatment with BH3•Me2S or sulfur. This gave P-stereogenic bisphosphines. To afford highly enantioenriched ligands, the bisphosphines were recrystallised to increase the enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. The sensitivity after deboronation to oxidation to the phosphine oxide was studied through 1H and 31P NMR spectra. To evaluate the new hemi-labile ligands, they were used as a coordinating ligand with Co2(CO)8 in a catalytic asymmetric intramolecular Pauson-Khand reaction of a 1,6-enyne to a cyclopentenone."],"dc:format":["text"],"dc:identifier.uri":["https://etheses.whiterose.ac.uk/id/eprint/1218/1/chehasnah_thesis_edited_2010.pdf"],"dc:publisher.commercial":["University of York"],"dc:publisher.department":["Chemistry (York)"],"dc:publisher.institution":["University of York"],"dc:relation.isreferencedby":["https://etheses.whiterose.ac.uk/id/eprint/1218/"],"dc:title":["Synthesis of P-Stereogenic Bisphosphine Ligands: Application as Hemi-labile Ligands in the Asymmetric Pauson-Khand Reaction"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["masters"],"dc:type.qualificationname":["M.Sc by research"]},"updated_at":"2026-07-24T06:04:19Z"}