{"id":{"repo_id":"nus","oai_identifier":"oai:scholarbank.nus.edu.sg:10635/50061"},"canonical_url":"https://search.dev.ndltd.org/etd/nus/oai:scholarbank.nus.edu.sg:10635/50061","repository":{"repo_id":"nus","name":"National University of Singapore","base_url":"https://scholarbank.nus.edu.sg/oai/request"},"display":{"title":"ORGANOCATALYTIC HALOFUNCTIONALIZATION OF OLEFINS","abstract":"Enantioselective halocyclization reactions are important for the synthesis of chiral heterocyclic compounds. In the first part of this thesis, a catalytic enantioselective bromocyclization of olefinic amides has been developed. The resulting enantioenriched 2-substituted 3-bromopiperidines can readily be transformed to 3-substituted piperidines through a silver salt-mediated rearrangement. This process has been applied to the synthesis of a dopaminergic drug, Preclamol. Next, an asymmetric synthesis of heterospirocycles through a double-halocyclization strategy which enabled access to a class of chiral novel spirocycles is reported. In a separate study, the intramolecular chloroamidation of olefinic substrates using diphenyl selenide as the catalyst is developed. The reaction conditions were found to be mild and suitable for a wide range of substrates including those which are acid labile. Lastly, preliminary results for the development of a novel proline-based amino-selenocarbamate catalysts were discussed. A derivative of the catalyst, the amino-selenoether, produced encouraging enantioselectivty for halolactonization reactions.","abstract_html":"Enantioselective halocyclization reactions are important for the synthesis of chiral heterocyclic compounds. In the first part of this thesis, a catalytic enantioselective bromocyclization of olefinic amides has been developed. The resulting enantioenriched 2-substituted 3-bromopiperidines can readily be transformed to 3-substituted piperidines through a silver salt-mediated rearrangement. This process has been applied to the synthesis of a dopaminergic drug, Preclamol. Next, an asymmetric synthesis of heterospirocycles through a double-halocyclization strategy which enabled access to a class of chiral novel spirocycles is reported. In a separate study, the intramolecular chloroamidation of olefinic substrates using diphenyl selenide as the catalyst is developed. The reaction conditions were found to be mild and suitable for a wide range of substrates including those which are acid labile. Lastly, preliminary results for the development of a novel proline-based amino-selenocarbamate catalysts were discussed. A derivative of the catalyst, the amino-selenoether, produced encouraging enantioselectivty for halolactonization reactions.","abstract_has_math":false,"creators":["TAY WEILIANG DANIEL"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-01-08","date_published":"2014-01-08","updated_at":"2026-07-24T03:32:18Z","subjects":["Organocatalyst, Halofunctionalization, Asymmetric, Bromoaminocyclization, Bromoetherification, Chloroamidation"],"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:creator","label":"Author","values":["TAY WEILIANG DANIEL"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2014-01-08"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://scholarbank.nus.edu.sg/handle/10635/50061"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Organocatalyst, Halofunctionalization, Asymmetric, Bromoaminocyclization, Bromoetherification, Chloroamidation"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://scholarbank.nus.edu.sg/bitstreams/c22de83a-7838-4b83-970e-be8d059da862/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Enantioselective halocyclization reactions are important for the synthesis of chiral heterocyclic compounds. In the first part of this thesis, a catalytic enantioselective bromocyclization of olefinic amides has been developed. The resulting enantioenriched 2-substituted 3-bromopiperidines can readily be transformed to 3-substituted piperidines through a silver salt-mediated rearrangement. This process has been applied to the synthesis of a dopaminergic drug, Preclamol. Next, an asymmetric synthesis of heterospirocycles through a double-halocyclization strategy which enabled access to a class of chiral novel spirocycles is reported. In a separate study, the intramolecular chloroamidation of olefinic substrates using diphenyl selenide as the catalyst is developed. The reaction conditions were found to be mild and suitable for a wide range of substrates including those which are acid labile. Lastly, preliminary results for the development of a novel proline-based amino-selenocarbamate catalysts were discussed. A derivative of the catalyst, the amino-selenoether, produced encouraging enantioselectivty for halolactonization reactions."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["830317d0c2af4f454e48e5772916bef2","3716768aa0232eee7984c9f029d815e2"]},{"key":"dc:title","label":"Title","values":["ORGANOCATALYTIC HALOFUNCTIONALIZATION OF OLEFINS"]}]}],"canonical_facts":{"dc:creator":["TAY WEILIANG DANIEL"],"dc:date.issued":["2014-01-08"],"dc:description.abstract":["Enantioselective halocyclization reactions are important for the synthesis of chiral heterocyclic compounds. In the first part of this thesis, a catalytic enantioselective bromocyclization of olefinic amides has been developed. The resulting enantioenriched 2-substituted 3-bromopiperidines can readily be transformed to 3-substituted piperidines through a silver salt-mediated rearrangement. This process has been applied to the synthesis of a dopaminergic drug, Preclamol. Next, an asymmetric synthesis of heterospirocycles through a double-halocyclization strategy which enabled access to a class of chiral novel spirocycles is reported. In a separate study, the intramolecular chloroamidation of olefinic substrates using diphenyl selenide as the catalyst is developed. The reaction conditions were found to be mild and suitable for a wide range of substrates including those which are acid labile. Lastly, preliminary results for the development of a novel proline-based amino-selenocarbamate catalysts were discussed. A derivative of the catalyst, the amino-selenoether, produced encouraging enantioselectivty for halolactonization reactions."],"dc:format.checksum.md5":["830317d0c2af4f454e48e5772916bef2","3716768aa0232eee7984c9f029d815e2"],"dc:identifier.uri":["https://scholarbank.nus.edu.sg/bitstreams/c22de83a-7838-4b83-970e-be8d059da862/download"],"dc:relation.isreferencedby":["https://scholarbank.nus.edu.sg/handle/10635/50061"],"dc:subject":["Organocatalyst, Halofunctionalization, Asymmetric, Bromoaminocyclization, Bromoetherification, Chloroamidation"],"dc:title":["ORGANOCATALYTIC HALOFUNCTIONALIZATION OF OLEFINS"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T03:32:18Z"}