The Volatile Constituents of the Coffee Flower (Coffea arabica L.)

Although coffee beans have been well studied, the volatile constituents of the coffee flower have not previously been investigated. An extract of coffee flower (Coffea arabica L.) was analyzed by GC-MS and found to contain a significant number of nitrogen-containing aromatic compounds as well as phenylethane derivatives. The novel epoxygeraniols (2,3-epoxygeraniol and 6,7-epoxygeraniol) were also detected as minor components. These epoxides were estimated to be an approximately equal mixture of both enantiomers by chiral GC analysis. Optically active 2,3-epoxygeraniols were synthesized by Sharp less's asymmetric epoxydation (AE), and 6,7-epoxygeraniols were prepared utilizing Sharp less's asymmetric dihydroxylation (AD) as a key step in high optical purities (96-99% ee). Epoxygeraniols were found to possess rosy and muguet-like aromas reminiscent of the living flower. Considerable differences of aroma were perceived between the enantiomers. (c) 1997 by John Wiley & Sons, Ltd.