NMR Verification of Diastereoselective Reduction of Substituted Cyclohexanones

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 5 Issue 2 (2000) pp 64-66

NMR Verification of Diastereoselective Reduction of Substituted Cyclohexanones

John W. Clavier, Joseph Fievet and Victoria Geisler*

Department of Chemistry, State University of West Georgia, Carrollton, GA 30118

Published online: 2 April 2000

Abstract. This experiment provides an ideal opportunity to integrate NMR spectroscopy, stereochemical principles, and the use of enzymes in the sophomore-level organic chemistry laboratory. Students work in teams and reduce either 2-methylcyclohexanone or 4- tert-butylcyclohexanone using common baker's yeast (Saccharomyces Cerevisiae) and sodium borohydride. The stereochemistry and diastereomeric ratios of alcohols produced are determined using proton NMR. The students are asked to rationalize the contrast in stereoselectivity observed with the different reducing agents. This experiment has an advantage over other baker's yeast reduction experiments [1, 4] in that the diastereoselectivity can be directly determined by NMR.

Key Words: Laboratories and Demonstrations; NMR spectroscopy; stereochemistry; organic chemistry

(*) Corresponding author. (E-mail: vgeisler@westga.edu)

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