Chiral Compounds and Green Chemistry in Undergraduate Organic Laboratories: Reduction of a Ketone by Sodium Borohydride and Baker's Yeast

Author Contact: npohl@iastate.edu

Summary

Chiral compounds can have unique properties and are becoming increasingly important in pharmaceutical, chemical and agricultural industries. In this laboratory exercise, students compare and contrast chemical vs. enzyme-mediated procedures for introducing chirality into a molecule and gain experience with the principles and experimental techniques used to prepare and separate enantiomers. Over the course of four, 3-hour lab periods, students characterize (1) racemic and enantiomerically enriched products of the sodium borohydride reduction of ethyl acetoacetate with and without the use of a L-tartaric acid and (2) products obtained with an enzyme-mediated reduction using Baker's yeast. This exercise provides a framework for discussing some of the unique challenges associated with using enzyme-mediated procedures for developing environmentally benign chiral syntheses.

Supplemental materials are provided on the J. Chem. Educ. website and include instructor notes and student handouts for the laboratory procedure and the chiral GC analysis.

Summary prepared May 2005 by Julie A. Haack, Department of Chemistry at the University of Oregon.

Category Descriptors

Chemistry Concepts

• Catalysis
• Chirality
• Oxidation/Reduction Chemistry

Laboratory Techniques

• Assembly of Reaction Apparatus
• Extraction
• Gas-Liquid Chromatography
• NMR Spectroscopy
• Optical Activity and Polarity
• Rotary Evaporation

Green Chemistry Principles

• Design Less Hazardous Chemical Syntheses
• Increase Energy Efficiency
• Prevent Waste
• Use Catalysts
• Use Safer Solvents/Reaction Conditions

Chemistry Subdiscipline

• Biochemistry
• Environmental Chemistry
• Organic Chemistry

Target Audience

• Colleges/Universities

Source

• Journal Articles