Asymmetric Synthesis and Absolute Configuration Determination of an Enantioenriched Alcohol: A Discovery-Based Undergraduate Laboratory Experiment
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| Title: | Asymmetric Synthesis and Absolute Configuration Determination of an Enantioenriched Alcohol: A Discovery-Based Undergraduate Laboratory Experiment |
|---|---|
| Language: | English |
| Authors: | King, Ryan P. (ORCID |
| Source: | Journal of Chemical Education. Mar 2020 97(3):793-800. |
| Availability: | 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 |
| Peer Reviewed: | Y |
| Page Count: | 8 |
| Publication Date: | 2020 |
| Document Type: | Journal Articles Reports - Descriptive |
| Education Level: | Higher Education Postsecondary Education |
| Descriptors: | Science Instruction, College Science, Undergraduate Study, Organic Chemistry, Scientific Concepts, Science Experiments, Science Laboratories, Laboratory Experiments |
| DOI: | 10.1021/acs.jchemed.9b00872 |
| ISSN: | 0021-9584 |
| Abstract: | 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. |
| Abstractor: | As Provided |
| Entry Date: | 2020 |
| Accession Number: | EJ1248701 |
| Database: | ERIC |
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