Stemarane Diterpenes and Diterpenoids

Leonelli, Francesca; Valletta, Alessio; Migneco, Luisa Maria; Bettolo, Rinaldo Marini

doi:10.3390/ijms20112627

Cited by 9 publications

(8 citation statements)

References 94 publications

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“…Induction of polyphenolic phytoalexin biosynthesis in response to UV exposure has been observed in numerous plants [246,247]. Non-polyphenolic phytoalexins can also be elicited by UV, e.g., labdane-related diterpenoids in rice [248] and terpenoid indole alkaloids in the Madagascar periwinkle (Catharanthus roseus (L.) G.Don) [249].…”

Section: Uv Radiationmentioning

confidence: 99%

Impact of Environmental Factors on Stilbene Biosynthesis

Valletta

Iozia

Leonelli

2021

Plants

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Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds.

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Section: Uv Radiationmentioning

confidence: 99%

Impact of Environmental Factors on Stilbene Biosynthesis

Valletta

Iozia

Leonelli

2021

Plants

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“…In the context of chemical synthesis, these two natural product families received much less attention compared with other tetracyclic LRDs. [37][38][39][40] Our insights into the retrosynthetic analysis of stemarane and betaerane diterpenoids 1-4 were greatly influenced by their biosynthesis, which usually involves a cyclization phase and an oxidation phase. We envisioned that diterpenoids 2-4 with higher oxidation levels could arise from the precursors 6 and 7, which contain the tetracyclic frameworks of natural products, through the C-H oxygenations at the C2 and C7 positions (Scheme 1C).…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of Stemarene and Betaerene Diterpenoids: Divergent Ring-Formation Strategy and Late-Stage C–H Functionalization

et al. 2022

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A unified protecting-group-free approach to two stemarene and two betaerene diterpenoids through a bioinspired two-phase strategy has been developed, and three of them were obtained for the first time via chemical synthesis. Starting from a common intermediate, two distinct tetracyclic frameworks containing diastereoisomeric bridged bicycles were constructed by divergent ring reorganization strategy. Late-stage C−H functionalization through xanthylation-oxygenation protocol furnished the corresponding oxygenated stereocenters or oxo functionality in high regio-and diastereoselective fashion within a complex hydrocarbon system. The stereochemical puzzles in (-)-2-acetoxybetaer-13(17)-ene and (+)-7-acetoxybetaer-13(17)-ene were first predicted by the comparison of DFT-NMR data with the reported data and later were unambiguously addressed through the total syntheses of natural products and three diastereomers.

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“…This goal was achieved by locating, in a substituted bicyclo[2.2.2]octane system, at a specific position, a suitably configurated leaving group the departure of which promoted the migration of the antiperiplanar C-C bond. Remarkable examples of such specificity were reported in the past in the frame of biogenetic syntheses of stemodane [4,5,9,[29][30][31][32][33], aphidicolane [30,31,[34][35][36][37][38] and stemarane [39][40][41][42][43][44], diterpenes and diterpenoids. As can be seen (Scheme 4), the bonds indicated by a green arrow migrate in one case (entry a) through the lower face of the molecule, while in entry b, the same bond migrates through the lower face owing to the different location of the leaving group.…”

Section: Biogenesismentioning

confidence: 99%