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ERIC Number: EJ1248701
Record Type: Journal
Publication Date: 2020-Mar
Pages: 8
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0021-9584
EISSN: N/A
Asymmetric Synthesis and Absolute Configuration Determination of an Enantioenriched Alcohol: A Discovery-Based Undergraduate Laboratory Experiment
King, Ryan P.; Wagner, Alexander J.; Burtea, Alexander; King, Susan M.
Journal of Chemical Education, v97 n3 p793-800 Mar 2020
An undergraduate organic chemistry experiment has been developed that features asymmetric synthesis of an enantioenriched secondary alcohol, followed by determination of its absolute configuration using the competing enantioselective conversion (CEC) method. Students are given a ketone and an unknown enantiomer of CBS (Corey-Bakshi-Shibata) catalyst. This reaction forms an enantioenriched secondary alcohol of unknown absolute configuration. Students then determine the absolute configuration via the CEC method. The CEC method is a modern application of the Horeau method that runs parallel reactions using both enantiomers of a chiral acyl-transfer catalyst, homobenzotetramisole (HBTM). Reactions are quenched concurrently, and reaction rates are compared using thin-layer chromatography (TLC) and/or [superscript 1]H nuclear magnetic resonance (NMR) spectroscopy to determine the fast and the slow reactions. By comparing the faster reaction to a previously determined mnemonic, the absolute configuration of the alcohol can be determined. From this information, students can then determine which enantiomer of CBS catalyst they used to form the enantioenriched alcohol. Both parts of this experiment were successfully completed in one 5 h lab section. This experiment provides an opportunity for discussion of important chemistry concepts including asymmetric synthesis, asymmetric catalysis, kinetic resolution, mechanism, transition state theory, and inert-atmosphere techniques.
Division of Chemical Education, Inc. and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A