{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/84290"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/84290","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Studies in Asymmetric Catalysis: Lewis Base Catalyzed, Enantioselective Addition of Trimethylsilyl Cyanide, Trimethylsilyltrifluoromethane, and Glycolate-Derived Silyl Ketene Acetals to Aldehydes","abstract":"A catalytic system involving silicon tetrachloride and a chiral, Lewis basic bisphosphoramide catalyst is effective for the addition of glycolate-derived silyl ketene acetals to aldehydes. The sense of diastereoselectivty could be modulated by changing the size of the substituents on the silyl ketene acetals. In general, the trimethylsilyl ketene acetals derived from methyl glycolates with a large protecting group on alpha-oxygen provide enantiomerically enriched alpha,beta-dihydroxy esters with high syn-diastereoselectivity, whereas the tert-butyldimethylsilyl ketene acetals derived from bulky esters of alpha-methoxy acetic acid provide enantiomerically enriched alpha,beta-dihydroxy esters with high anti-diastereoselecitvity. The observed diastereoselectivity and reactivity could be rationalized by the analysis of six open transition states with the aid of computational calculation.","abstract_html":"A catalytic system involving silicon tetrachloride and a chiral, Lewis basic bisphosphoramide catalyst is effective for the addition of glycolate-derived silyl ketene acetals to aldehydes. The sense of diastereoselectivty could be modulated by changing the size of the substituents on the silyl ketene acetals. In general, the trimethylsilyl ketene acetals derived from methyl glycolates with a large protecting group on alpha-oxygen provide enantiomerically enriched alpha,beta-dihydroxy esters with high syn-diastereoselectivity, whereas the tert-butyldimethylsilyl ketene acetals derived from bulky esters of alpha-methoxy acetic acid provide enantiomerically enriched alpha,beta-dihydroxy esters with high anti-diastereoselecitvity. The observed diastereoselectivity and reactivity could be rationalized by the analysis of six open transition states with the aid of computational calculation.","abstract_has_math":false,"creators":["Chung, Won-Jin"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":["Denmark, Scott E."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T22:13:49Z","date_published":"2015-09-25T22:13:49Z","updated_at":"2026-07-22T22:26:22Z","subjects":["Chemistry, Organic"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3314748"],"render_values":[{"text":"(MiAaPQ)AAI3314748","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/84290","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Denmark, Scott E."]},{"key":"dc:creator","label":"Author","values":["Chung, Won-Jin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T22:13:49Z","10000-01-01","2008"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Organic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/84290","(MiAaPQ)AAI3314748"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A catalytic system involving silicon tetrachloride and a chiral, Lewis basic bisphosphoramide catalyst is effective for the addition of glycolate-derived silyl ketene acetals to aldehydes. The sense of diastereoselectivty could be modulated by changing the size of the substituents on the silyl ketene acetals. In general, the trimethylsilyl ketene acetals derived from methyl glycolates with a large protecting group on alpha-oxygen provide enantiomerically enriched alpha,beta-dihydroxy esters with high syn-diastereoselectivity, whereas the tert-butyldimethylsilyl ketene acetals derived from bulky esters of alpha-methoxy acetic acid provide enantiomerically enriched alpha,beta-dihydroxy esters with high anti-diastereoselecitvity. The observed diastereoselectivity and reactivity could be rationalized by the analysis of six open transition states with the aid of computational calculation.","Made available in DSpace on 2015-09-25T22:13:49Z (GMT). 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The sense of diastereoselectivty could be modulated by changing the size of the substituents on the silyl ketene acetals. In general, the trimethylsilyl ketene acetals derived from methyl glycolates with a large protecting group on alpha-oxygen provide enantiomerically enriched alpha,beta-dihydroxy esters with high syn-diastereoselectivity, whereas the tert-butyldimethylsilyl ketene acetals derived from bulky esters of alpha-methoxy acetic acid provide enantiomerically enriched alpha,beta-dihydroxy esters with high anti-diastereoselecitvity. The observed diastereoselectivity and reactivity could be rationalized by the analysis of six open transition states with the aid of computational calculation.","Made available in DSpace on 2015-09-25T22:13:49Z (GMT). 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