{"id":{"repo_id":"utswmed","oai_identifier":"oai:utswmed-ir.tdl.org:2152.5/10396"},"canonical_url":"https://search.dev.ndltd.org/etd/utswmed/oai:utswmed-ir.tdl.org:2152.5/10396","repository":{"repo_id":"utswmed","name":"University of Texas Southwestern Medical Center","base_url":"https://utswmed-ir.tdl.org/server/oai/request"},"display":{"title":"Iridium-Catalyzed Enantioselective Allylation of Alkenyl Boronates","abstract":"Organoboronic esters are highly functionalizable synthetic intermediates owing to their unique reactivity that allows for pre-complexation with organometallic reagents to form boronates, which can then engage in bimolecular reactions. Furthermore, incorporation of boronic esters into their corresponding products allows for subsequent diversification through a wide variety of synthetically useful transformations. Some of the most valuable transformations of organoboronic esters involve 1,2-metalate shifts from anionic "ate" complexes. First described are select methodologies that showcase the use of this 1,2-metalate rearrangement from organoboron compounds over the past several decades. This includes 1,2-metalate shifts onto sp3 and sp2-hybridized adjacent carbons through intramolecular expulsion of the leaving group, as well as stoichiometric use of external electrophiles. Select catalyst-promoted 1,2-metalate rearrangements will be discussed that engage alkenyl boronates and in some cases render the migration stereoselective. Additionally, select examples of iridium-catalyzed nucleophilic substitution reactions will be examined. The second chapter describes the reaction of alkenyl boronates with allylic carbonates to generate tertiary bis-homoallyl boronic esters with high enantioselectivity and 1,3-diastereocontrol. The three-component coupling features an Ir(phosphoramidite) complex, which catalyzes a kinetic resolution of secondary allylic carbonates. Alkenyl boronate addition to an Ir(π-allyl) intermediate and a 1,2-metalate shift provides the observed products. Synthetic transformations of the tertiary boronic ester provide access to quaternary stereocenters in a diastereoselective manner. An extension to trisubstituted olefins sets three-contiguous stereocenters and provides initial insights into the diastereoselectivity of the reaction through a conserved syn-addition pathway. The final chapter provides detailed mechanistic investigations that outline the overall catalytic cycle and reveal trends in reactivity and selectivity. Analysis of relative stereochemistry in a variety of 1,1-disubtituted alkenyl boronates provides insight into the transition state of the addition and indicates a concerted pathway. Kinetic analysis of the reaction revealed the kinetic order dependence in boronate, catalyst, and both the slow- and fast-reacting enantiomer of allylic carbonate as well as the turnover-limiting step of the reaction. Hammett studies explored substituent effects in both aryl-derived alkenyl boronates and aryl carbonates. Nucleophile-specific parameters N and sN for the alkenyl boronate complex were determined and compared to other classes of compounds. Initial investigations into the migratory selectivity of the 1,2-metalate shift were also examined using (bis)alkenyl boronates.","abstract_html":"Organoboronic esters are highly functionalizable synthetic intermediates owing to their unique reactivity that allows for pre-complexation with organometallic reagents to form boronates, which can then engage in bimolecular reactions. Furthermore, incorporation of boronic esters into their corresponding products allows for subsequent diversification through a wide variety of synthetically useful transformations. Some of the most valuable transformations of organoboronic esters involve 1,2-metalate shifts from anionic "ate" complexes. First described are select methodologies that showcase the use of this 1,2-metalate rearrangement from organoboron compounds over the past several decades. This includes 1,2-metalate shifts onto sp3 and sp2-hybridized adjacent carbons through intramolecular expulsion of the leaving group, as well as stoichiometric use of external electrophiles. Select catalyst-promoted 1,2-metalate rearrangements will be discussed that engage alkenyl boronates and in some cases render the migration stereoselective. Additionally, select examples of iridium-catalyzed nucleophilic substitution reactions will be examined. The second chapter describes the reaction of alkenyl boronates with allylic carbonates to generate tertiary bis-homoallyl boronic esters with high enantioselectivity and 1,3-diastereocontrol. The three-component coupling features an Ir(phosphoramidite) complex, which catalyzes a kinetic resolution of secondary allylic carbonates. Alkenyl boronate addition to an Ir(π-allyl) intermediate and a 1,2-metalate shift provides the observed products. Synthetic transformations of the tertiary boronic ester provide access to quaternary stereocenters in a diastereoselective manner. An extension to trisubstituted olefins sets three-contiguous stereocenters and provides initial insights into the diastereoselectivity of the reaction through a conserved syn-addition pathway. The final chapter provides detailed mechanistic investigations that outline the overall catalytic cycle and reveal trends in reactivity and selectivity. Analysis of relative stereochemistry in a variety of 1,1-disubtituted alkenyl boronates provides insight into the transition state of the addition and indicates a concerted pathway. Kinetic analysis of the reaction revealed the kinetic order dependence in boronate, catalyst, and both the slow- and fast-reacting enantiomer of allylic carbonate as well as the turnover-limiting step of the reaction. Hammett studies explored substituent effects in both aryl-derived alkenyl boronates and aryl carbonates. Nucleophile-specific parameters N and sN for the alkenyl boronate complex were determined and compared to other classes of compounds. Initial investigations into the migratory selectivity of the 1,2-metalate shift were also examined using (bis)alkenyl boronates.","abstract_has_math":false,"creators":["Davis, Colton Randall"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Qin, Tian","Tambar, Uttam","De Brabander, Jef K.","Ready, Joseph M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2024,"date_issued":"2024-09-20T22:10:00Z","date_published":"2024-09-20T22:10:00Z","updated_at":"2026-07-24T05:52:17Z","subjects":["Stereoisomerism","Allyl Compounds","Boron Compounds","Carbonates","Catalysis","Iridium"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["1456721224"],"render_values":[{"text":"1456721224","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/2152.5/10396","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Qin, Tian","Tambar, Uttam","De Brabander, Jef K.","Ready, Joseph M."]},{"key":"dc:creator","label":"Author","values":["Davis, Colton Randall"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2024-09-20T22:10:00Z","2022-08","August 2022","2024-09-20T22:10:01Z"]},{"key":"dc:type","label":"Dc Type","values":["Thesis","text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Stereoisomerism","Allyl Compounds","Boron Compounds","Carbonates","Catalysis","Iridium"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2152.5/10396","1456721224"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Organoboronic esters are highly functionalizable synthetic intermediates owing to their unique reactivity that allows for pre-complexation with organometallic reagents to form boronates, which can then engage in bimolecular reactions. Furthermore, incorporation of boronic esters into their corresponding products allows for subsequent diversification through a wide variety of synthetically useful transformations. Some of the most valuable transformations of organoboronic esters involve 1,2-metalate shifts from anionic "ate" complexes. First described are select methodologies that showcase the use of this 1,2-metalate rearrangement from organoboron compounds over the past several decades. This includes 1,2-metalate shifts onto sp3 and sp2-hybridized adjacent carbons through intramolecular expulsion of the leaving group, as well as stoichiometric use of external electrophiles. Select catalyst-promoted 1,2-metalate rearrangements will be discussed that engage alkenyl boronates and in some cases render the migration stereoselective. Additionally, select examples of iridium-catalyzed nucleophilic substitution reactions will be examined. The second chapter describes the reaction of alkenyl boronates with allylic carbonates to generate tertiary bis-homoallyl boronic esters with high enantioselectivity and 1,3-diastereocontrol. The three-component coupling features an Ir(phosphoramidite) complex, which catalyzes a kinetic resolution of secondary allylic carbonates. Alkenyl boronate addition to an Ir(π-allyl) intermediate and a 1,2-metalate shift provides the observed products. Synthetic transformations of the tertiary boronic ester provide access to quaternary stereocenters in a diastereoselective manner. An extension to trisubstituted olefins sets three-contiguous stereocenters and provides initial insights into the diastereoselectivity of the reaction through a conserved syn-addition pathway. The final chapter provides detailed mechanistic investigations that outline the overall catalytic cycle and reveal trends in reactivity and selectivity. Analysis of relative stereochemistry in a variety of 1,1-disubtituted alkenyl boronates provides insight into the transition state of the addition and indicates a concerted pathway. Kinetic analysis of the reaction revealed the kinetic order dependence in boronate, catalyst, and both the slow- and fast-reacting enantiomer of allylic carbonate as well as the turnover-limiting step of the reaction. Hammett studies explored substituent effects in both aryl-derived alkenyl boronates and aryl carbonates. Nucleophile-specific parameters N and sN for the alkenyl boronate complex were determined and compared to other classes of compounds. Initial investigations into the migratory selectivity of the 1,2-metalate shift were also examined using (bis)alkenyl boronates."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Iridium-Catalyzed Enantioselective Allylation of Alkenyl Boronates"]}]}],"canonical_facts":{"dc:contributor":["Qin, Tian","Tambar, Uttam","De Brabander, Jef K.","Ready, Joseph M."],"dc:creator":["Davis, Colton Randall"],"dc:date":["2024-09-20T22:10:00Z","2022-08","August 2022","2024-09-20T22:10:01Z"],"dc:description":["Organoboronic esters are highly functionalizable synthetic intermediates owing to their unique reactivity that allows for pre-complexation with organometallic reagents to form boronates, which can then engage in bimolecular reactions. Furthermore, incorporation of boronic esters into their corresponding products allows for subsequent diversification through a wide variety of synthetically useful transformations. Some of the most valuable transformations of organoboronic esters involve 1,2-metalate shifts from anionic "ate" complexes. First described are select methodologies that showcase the use of this 1,2-metalate rearrangement from organoboron compounds over the past several decades. This includes 1,2-metalate shifts onto sp3 and sp2-hybridized adjacent carbons through intramolecular expulsion of the leaving group, as well as stoichiometric use of external electrophiles. Select catalyst-promoted 1,2-metalate rearrangements will be discussed that engage alkenyl boronates and in some cases render the migration stereoselective. Additionally, select examples of iridium-catalyzed nucleophilic substitution reactions will be examined. The second chapter describes the reaction of alkenyl boronates with allylic carbonates to generate tertiary bis-homoallyl boronic esters with high enantioselectivity and 1,3-diastereocontrol. The three-component coupling features an Ir(phosphoramidite) complex, which catalyzes a kinetic resolution of secondary allylic carbonates. Alkenyl boronate addition to an Ir(π-allyl) intermediate and a 1,2-metalate shift provides the observed products. Synthetic transformations of the tertiary boronic ester provide access to quaternary stereocenters in a diastereoselective manner. An extension to trisubstituted olefins sets three-contiguous stereocenters and provides initial insights into the diastereoselectivity of the reaction through a conserved syn-addition pathway. The final chapter provides detailed mechanistic investigations that outline the overall catalytic cycle and reveal trends in reactivity and selectivity. Analysis of relative stereochemistry in a variety of 1,1-disubtituted alkenyl boronates provides insight into the transition state of the addition and indicates a concerted pathway. Kinetic analysis of the reaction revealed the kinetic order dependence in boronate, catalyst, and both the slow- and fast-reacting enantiomer of allylic carbonate as well as the turnover-limiting step of the reaction. Hammett studies explored substituent effects in both aryl-derived alkenyl boronates and aryl carbonates. Nucleophile-specific parameters N and sN for the alkenyl boronate complex were determined and compared to other classes of compounds. Initial investigations into the migratory selectivity of the 1,2-metalate shift were also examined using (bis)alkenyl boronates."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2152.5/10396","1456721224"],"dc:language":["en"],"dc:subject":["Stereoisomerism","Allyl Compounds","Boron Compounds","Carbonates","Catalysis","Iridium"],"dc:title":["Iridium-Catalyzed Enantioselective Allylation of Alkenyl Boronates"],"dc:type":["Thesis","text"]},"updated_at":"2026-07-24T05:52:17Z"}