2026-09-22T02:31:38Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/84290 2023-07-11 col_2142_5131 col_2142_14789 com_2142_5130 com_2142_14788 com_2142_8903

Denmark, Scott E. Chung, Won-Jin 2015-09-25T22:13:49Z 2015-09-25T22:13:49Z 10000-01-01 2008 2008 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). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3314748.pdf: 6764811 bytes, checksum: f5e629aeae570b15d09b1a0d3058e4b1 (MD5) Previous issue date: 2008 Embargo set by: Seth Robbins for item 85571 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 418 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. http://hdl.handle.net/2142/84290 (MiAaPQ)AAI3314748 eng Chemistry, Organic Studies in Asymmetric Catalysis: Lewis Base Catalyzed, Enantioselective Addition of Trimethylsilyl Cyanide, Trimethylsilyltrifluoromethane, and Glycolate-Derived Silyl Ketene Acetals to Aldehydes text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.