Stereoisomeric Flavor Compounds LXXXII Dill Ether and Its Stereoisomers: Synthesis and Enantioselective Analysis

Biosynthesis of Stereoisomers of Dill Ether and Wine Lactone by Pleurotus sapidus

“…From the available pool of acetyl-CoA molecules, isopentenyl pyrophosphate (IPP) is synthesized via the mevalonate pathway as the only known pathway toward terpenoid compounds in fungi. Theoretically, this results in up to two 13 C labels of the IPP molecules. 38 IPP is then further converted via geranyl pyrophosphate (GPP) to dill ether and wine lactone with theoretically up to four 13 C labels.…”

“…This procedure was repeated with (4S)-limonene (3B) (Alfa Aesar) to produce a diastereomeric mixture of (4S,8RS)-p-menth-1-en-9-ol (4B/4D). The structures of the synthesized products were confirmed by 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy. The mass spectra were in agreement with those reported by Guth et al 21 Retention indices (RIs) on two GC columns of different polarity were in agreement with those from literature references (RI wax , 1931/1934; RI DB5 , 1297/1298).…”

Formation of Diastereomeric Dihydromenthofurolactones by Cystostereum murrayi and Aroma Dilution Analysis Based on Dynamic Headspace Extraction

“…However, the stereoisomers with a trans-connection in the tetrahydrofuran ring system are unlikely to be biosynthesized via natural pathways due to the resulting ring strain. 33 The odor impressions of the four cis-stereoisomers vary from a characteristic dill-like odor (3a) to rather herbal, flowery, tarragon-like, sweet, and minty odors (3b, 7c, and 7d). 4,34 Natural sources for dill ethers are dill for enantiopure 3a and different honey varieties for all four cis-isomers.…”

“…Due to the three stereogenic centers of the dill ethers, eight stereoisomers can theoretically be formed (Figure ). However, the stereoisomers with a trans -connection in the tetrahydrofuran ring system are unlikely to be biosynthesized via natural pathways due to the resulting ring strain . The odor impressions of the four cis -stereoisomers vary from a characteristic dill-like odor ( 3a ) to rather herbal, flowery, tarragon-like, sweet, and minty odors ( 3b , 7c , and 7d ). , Natural sources for dill ethers are dill for enantiopure 3a and different honey varieties for all four cis -isomers. − Based on this occurrence, n -pentane/diethyl ether extracts of these natural sources were used as references for the analysis via MDGC.…”

“…Due to this fact, 14 and 15 have four stereogenic centers, which results in a total of 16 possible stereoisomers. Assuming again that the isomers with a trans -connection are unlikely to be formed via natural pathways, eight different cis -stereoisomers could theoretically be formed. Indeed, employing 2D-NMR experiments confirmed the cis -connection of 14 / 15 and 16 .…”