{"id":{"repo_id":"east-anglia","oai_identifier":"oai:ueaeprints.uea.ac.uk:53373"},"canonical_url":"https://search.dev.ndltd.org/etd/east-anglia/oai:ueaeprints.uea.ac.uk:53373","repository":{"repo_id":"east-anglia","name":"University of East Anglia","base_url":"https://ueaeprints.uea.ac.uk/cgi/oai2"},"display":{"title":"Synthesis of Functionalised Cobalt Sandwich Complexes for Application in Asymmetric Catalysis","abstract":"The reaction of cobalt sandwich complex (η5-(N,N-dimethylaminomethyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and N-acetyl-D-phenylalanine gave planar chiral palladacycle di-μ-chloridebis[(η5-(Sp)-2-(N,N-dimethylaminomethyl)cyclopentadienyl,1-C,3′-N)(η4-tetraphenylcyclobutadiene)cobalt]dipalladium in 92% ee, 64% yield. The enantioselective palladation methodology was subsequently applied to corresponding N,N-diethyl (82% ee, 39% yield) and pyrrolidinyl (>98% ee, 43% yield) cobalt sandwich complexes. The complex derived from the pyrrolidinyl ligand was tested as a catalyst in the allylic imidate rearrangement (up to 99 % ee), showcasing comparable reactivity and selectivity to that seen in literature examples. The diastereoselective palladation of a range of (η5-oxazolinylcyclopentadienyl-(4-tetraphenylcyclobutadiene)cobalt complexes was tested by reaction with palladium acetate. Acetate dimer di-μ-acetatobis[(η5-(S)-(Sp)-2-(2’-4’-methylcyclohexyl)oxazolinyl)cyclopentadienyl, 1-C, 3’-N)(η4-tetraphenylcyclobutadiene)cobalt(I)]dipalladium(II) precipitated as a single diasteroisomer from the reaction media and was tested as a catalyst in the allylic imidate rearrangement (80% ee). In addition, access to modified sandwich complexes was realised using the Friedel-Crafts reaction. Complex (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt underwent reaction with acid chlorides/aluminum chloride to give exclusively para-acylation. Reaction of unsymmetrical bis-aryl alkynes [PhCC(o-RC6H4), R = Me, iPr] with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Friedel-Crafts reaction on the major isomers gave exclusively the para-acylation of the unsubstituted phenyl groups.","abstract_html":"The reaction of cobalt sandwich complex (η5-(N,N-dimethylaminomethyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and N-acetyl-D-phenylalanine gave planar chiral palladacycle di-μ-chloridebis[(η5-(Sp)-2-(N,N-dimethylaminomethyl)cyclopentadienyl,1-C,3′-N)(η4-tetraphenylcyclobutadiene)cobalt]dipalladium in 92% ee, 64% yield. The enantioselective palladation methodology was subsequently applied to corresponding N,N-diethyl (82% ee, 39% yield) and pyrrolidinyl (>98% ee, 43% yield) cobalt sandwich complexes. The complex derived from the pyrrolidinyl ligand was tested as a catalyst in the allylic imidate rearrangement (up to 99 % ee), showcasing comparable reactivity and selectivity to that seen in literature examples. The diastereoselective palladation of a range of (η5-oxazolinylcyclopentadienyl-(4-tetraphenylcyclobutadiene)cobalt complexes was tested by reaction with palladium acetate. Acetate dimer di-μ-acetatobis[(η5-(S)-(Sp)-2-(2’-4’-methylcyclohexyl)oxazolinyl)cyclopentadienyl, 1-C, 3’-N)(η4-tetraphenylcyclobutadiene)cobalt(I)]dipalladium(II) precipitated as a single diasteroisomer from the reaction media and was tested as a catalyst in the allylic imidate rearrangement (80% ee). In addition, access to modified sandwich complexes was realised using the Friedel-Crafts reaction. Complex (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt underwent reaction with acid chlorides/aluminum chloride to give exclusively para-acylation. Reaction of unsymmetrical bis-aryl alkynes [PhCC(o-RC6H4), R = Me, iPr] with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Friedel-Crafts reaction on the major isomers gave exclusively the para-acylation of the unsubstituted phenyl groups.","abstract_has_math":false,"creators":["Cassar, Doyle"],"institution":"University of East Anglia","degree_name":"phd","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-09","date_published":"2014-09","updated_at":"2026-07-24T02:12:08Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Cassar, Doyle"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-09"]},{"key":"dc:date.issued","label":"Date","values":["2014-09"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Chemistry"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of East Anglia"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://ueaeprints.uea.ac.uk/id/eprint/53373/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["phd"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://ueaeprints.uea.ac.uk/id/eprint/53373/1/Doyle_Joseph_Cassar_%283425231%29_-_Synthesis_of_Functionalised_Cobalt_Sandwich_Complexes_for_Application_in_Asymmetric_Catalysis.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The reaction of cobalt sandwich complex (η5-(N,N-dimethylaminomethyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and N-acetyl-D-phenylalanine gave planar chiral palladacycle di-μ-chloridebis[(η5-(Sp)-2-(N,N-dimethylaminomethyl)cyclopentadienyl,1-C,3′-N)(η4-tetraphenylcyclobutadiene)cobalt]dipalladium in 92% ee, 64% yield. The enantioselective palladation methodology was subsequently applied to corresponding N,N-diethyl (82% ee, 39% yield) and pyrrolidinyl (>98% ee, 43% yield) cobalt sandwich complexes. The complex derived from the pyrrolidinyl ligand was tested as a catalyst in the allylic imidate rearrangement (up to 99 % ee), showcasing comparable reactivity and selectivity to that seen in literature examples. The diastereoselective palladation of a range of (η5-oxazolinylcyclopentadienyl-(4-tetraphenylcyclobutadiene)cobalt complexes was tested by reaction with palladium acetate. Acetate dimer di-μ-acetatobis[(η5-(S)-(Sp)-2-(2’-4’-methylcyclohexyl)oxazolinyl)cyclopentadienyl, 1-C, 3’-N)(η4-tetraphenylcyclobutadiene)cobalt(I)]dipalladium(II) precipitated as a single diasteroisomer from the reaction media and was tested as a catalyst in the allylic imidate rearrangement (80% ee). In addition, access to modified sandwich complexes was realised using the Friedel-Crafts reaction. Complex (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt underwent reaction with acid chlorides/aluminum chloride to give exclusively para-acylation. Reaction of unsymmetrical bis-aryl alkynes [PhCC(o-RC6H4), R = Me, iPr] with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Friedel-Crafts reaction on the major isomers gave exclusively the para-acylation of the unsubstituted phenyl groups."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Synthesis of Functionalised Cobalt Sandwich Complexes for Application in Asymmetric Catalysis"]}]}],"canonical_facts":{"dc:creator":["Cassar, Doyle"],"dc:date":["2014-09"],"dc:date.issued":["2014-09"],"dc:description.abstract":["The reaction of cobalt sandwich complex (η5-(N,N-dimethylaminomethyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and N-acetyl-D-phenylalanine gave planar chiral palladacycle di-μ-chloridebis[(η5-(Sp)-2-(N,N-dimethylaminomethyl)cyclopentadienyl,1-C,3′-N)(η4-tetraphenylcyclobutadiene)cobalt]dipalladium in 92% ee, 64% yield. The enantioselective palladation methodology was subsequently applied to corresponding N,N-diethyl (82% ee, 39% yield) and pyrrolidinyl (>98% ee, 43% yield) cobalt sandwich complexes. The complex derived from the pyrrolidinyl ligand was tested as a catalyst in the allylic imidate rearrangement (up to 99 % ee), showcasing comparable reactivity and selectivity to that seen in literature examples. The diastereoselective palladation of a range of (η5-oxazolinylcyclopentadienyl-(4-tetraphenylcyclobutadiene)cobalt complexes was tested by reaction with palladium acetate. Acetate dimer di-μ-acetatobis[(η5-(S)-(Sp)-2-(2’-4’-methylcyclohexyl)oxazolinyl)cyclopentadienyl, 1-C, 3’-N)(η4-tetraphenylcyclobutadiene)cobalt(I)]dipalladium(II) precipitated as a single diasteroisomer from the reaction media and was tested as a catalyst in the allylic imidate rearrangement (80% ee). In addition, access to modified sandwich complexes was realised using the Friedel-Crafts reaction. Complex (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt underwent reaction with acid chlorides/aluminum chloride to give exclusively para-acylation. Reaction of unsymmetrical bis-aryl alkynes [PhCC(o-RC6H4), R = Me, iPr] with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Friedel-Crafts reaction on the major isomers gave exclusively the para-acylation of the unsubstituted phenyl groups."],"dc:format":["application/pdf"],"dc:identifier.uri":["https://ueaeprints.uea.ac.uk/id/eprint/53373/1/Doyle_Joseph_Cassar_%283425231%29_-_Synthesis_of_Functionalised_Cobalt_Sandwich_Complexes_for_Application_in_Asymmetric_Catalysis.pdf"],"dc:language":["en"],"dc:publisher.department":["School of Chemistry"],"dc:publisher.institution":["University of East Anglia"],"dc:relation.isreferencedby":["https://ueaeprints.uea.ac.uk/id/eprint/53373/"],"dc:title":["Synthesis of Functionalised Cobalt Sandwich Complexes for Application in Asymmetric Catalysis"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T02:12:08Z"}