Synthesis of Both Enantiomers of Methyl 3-methyloctanoate, Key Component for the Scent of African Orchids and Determination of their Absolute Configuration

Abstract

Synthesis of enantiomers of methyl 3-methyloctanoate 2 was achieved starting from enantiomers of methyl 3-hydroxy-2-methylpropanoate 3 in 9 steps. (S)-Enantiomer was shown to be identical with the naturally occurring isomer by GC analysis using a capillary column with chiral stationary phase. Interestingly, unnatural (R)-enantiomer has stronger floral note than natural (S)-enantiomer.

Key Words:

• (S)- and (R)-methyl 3-methyloctanoate
• Grignard coupling
• Aerangis confusa
• Aerangis kirkii
• Orchid scent