Selective Reduction of Hindered Chiral Ketones. Analysis of Diastereoisomeric Products by Gas Chromatography and Polarimetry
Key Points
To explore the reduction of hindered chiral ketones and analyze the resulting diastereomers.
Performed reduction of chiral ketones with sodium borohydride
Analyzed products using gas chromatography (GC)
Determined specific rotations with polarimetry
Formation of two distinct diastereomers observed
Percentage of each isomer quantified through GC analysis
Specific rotations helped confirm the identity of the isomers
Abstract
The reduction of hindered chiral ketones with sodium borohydride can be analyzed by GC and polarimetry and has been revealed to be a straightforward laboratory experiment for undergraduate students to obtain contact with stereoselective reactions. The characteristic feature of this reaction, consisting in the formation of two diastereomers, is the possibility of determining the percentage of each isomer formed by GC analysis and by polarimetry using the values of the specific rotation of the mixture and the specific rotations of the pure isomers.