Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols

• Marek Kõllo,
• Marje Kasari,
• Villu Kasari,
• Tõnis Pehk,
• Ivar Järving,
• Margus Lopp,
• Arvi Jõers and
• Tõnis Kanger

Beilstein J. Org. Chem. 2021, 17, 581–588, doi:10.3762/bjoc.17.52

• toxic oxidants. Keywords: chemoenzymatic synthesis; cortisol; hydroxylation; secosterol; whole-cell catalysis; Introduction Developments in the chemistry of steroids have stimulated extensive research interest in the exploration of new synthetic methods since the 1960s. Advances in synthetic biology

• synthetic methods for secosteroids is wide. However, usually these are multistep sequences exploiting toxic oxidants. Marine invertebrates are a rich source of oxidated and highly functionalized steroidal metabolites, including secosteroids. Since the first isolation of 9,11-secosterol from

• approach to 9,11-secosterols is depicted in the retrosynthetic analysis in Scheme 1. There are two key steps in obtaining the skeleton of the secosterol. The first is (di)hydroxylation at C9 (C11), and the second is C9–C11-bond cleavage, which can be carried out by a well-developed chemical oxidation of

Secondary metabolome and its defensive role in the aeolidoidean Phyllodesmium longicirrum, (Gastropoda, Heterobranchia, Nudibranchia)

• Alexander Bogdanov,
• Cora Hertzer,
• Stefan Kehraus,
• Samuel Nietzer,
• Sven Rohde,
• Peter J. Schupp,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2017, 13, 502–519, doi:10.3762/bjoc.13.50

• , and two further ones to the decaline ring, thus requiring a further ring in 1. Considering this, a secosterol backbone was likely. Also, the 13C NMR resonance of the oxygenated methylene at δC 59.1 (C-11) is characteristic for marine-derived secosterols [21]. The 1H-1H spin system C only including H2

• ]) and from those of the epoxy-secosterol reported by Anta et al. (δC 65.5 and δC 58.1, respectively; [24]). The downfield shift, observed for these carbons in 1, results from the cleavage of the epoxide ring, and 13C values around δC 70–80 as observed for 1 are characteristic for hydroxylated carbons

• – compared to the mushroom shape of Sarcophyton. Moreover, no typical gorgonian diterpenes (e.g., pseudopterosines, [55]) were isolated from P. longicirrum. As stated before, it is more likely that the secosterol is produced by zooxanthellae independently from its host and/or the Sarcophyton soft corals

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162