Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• potentially arise from the achiral sesquiterpene hydrocarbon germacrene B. Not only compounds isolated from natural sources, but also synthetic compounds are dicussed, with the aim to give a rationale for the structural assignment for each compound. A total number of 64 compounds is presented, with 131 cited

• references. Keywords: biosynthesis; configuration determination; germacrene B; structure elucidation; terpenes; Introduction Terpenoids constitute the largest class of natural products with ca. 100,000 known compounds. Biosynthetically, all terpenoids are derived from only a few acyclic precursors

• - (selinane) or 5-7-bicyclic (guaiane) sesquiterpenes. We have recently summarised the accumulated knowledge about sesquiterpenes derived from germacrene A (2) [12] and hedycaryol (3) [13]. Now we wish to provide a review on the known chemical space of sesquiterpenes derived from germacrene B (1) (Scheme 2

Analysis of sesquiterpene hydrocarbons in grape berry exocarp (Vitis vinifera L.) using in vivo-labeling and comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC–MS)

• Philipp P. Könen and
• Matthias Wüst

Beilstein J. Org. Chem. 2019, 15, 1945–1961, doi:10.3762/bjoc.15.190

• d2-DOX six deuterium atoms were incorporated at most. This data indicates that the biosynthesis of β-elemene, (+)-valencene and α-guaiene is achieved via germacrene A. Biosynthesis of sesquiterpene hydrocarbons via (E,E)-germacrene B The mechanisms proposed by Steele et al. for the formation of

• selina-3,7(11)-diene and γ-elemene via (E,E)-germacrene B are consistent with our results (Scheme 6) [9]. In Figure 9 the recorded mass spectra of d0-γ-elemene and d9-γ-elemene are shown as examples. Biosynthesis of guaiazulene, δ-elemene, guaia-6,9-diene and δ-selinene The formation of the aromatic

• )-germacrene B. The shown deuterium incorporation results from feeding experiments of exocarp (Lemberger cultivar) using the precursor d3-MVL. Possible synthesis of d9-guaiazulene, d9-δ-elemene, d9-guaia-6,9-diene and d9-δ-selinene via germacrene C after administration of [6,6,6-2H3]-(±)-mevalonolactone (d3

A detailed view on 1,8-cineol biosynthesis by Streptomyces clavuligerus

• Jan Rinkel,
• Patrick Rabe,
• Laura zur Horst and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2016, 12, 2317–2324, doi:10.3762/bjoc.12.225

• monooxygenases and acyl transferases [12][13]. Very few cases are known in which terpene cyclases generate an achiral product as exemplified by the monoterpene 1,8-cineol (eucalyptol, 1) and the sesquiterpenes germacrene B (2) and α-humulene (3) (Figure 1). A direct 1,6-cyclisation of the monoterpene precursor