Total Syntheses of Sesterterpenoid Ansellones A and B, and Phorbadione

Zhang, Wei; Yao, Hongliang; Yu, Jingxun; Tong, Rongbiao

doi:10.1002/ange.201701879

Cited by 10 publications

(3 citation statements)

References 65 publications

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“…1b), various head-to-tail (HTT) or tail-to-head (TTH) cyclized hydrocarbons are delivered from identical precursors, utilizing the same reaction pathway in a shape-selective transformation. For example, geranylgeraniolpyrophosphate (6) is the sole precursor for the taxadiene 7, that upon further enzymatic oxidations and tailoring give rise to taxol (10) 37 , to primaradiene (8, → diaporthein B, 11) 38 and to casbene (9, → japodagrin, 12) 39 . Such a predictable control of molecular conformation in solution thereby steering the selectivity of the reaction 14…”

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confidence: 99%

Enzyme-like polyene cyclizations catalyzed by dynamic, self-assembled, supramolecular fluoro alcohol-amine clusters

et al. 2023

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Terpene cyclases catalyze one of the most powerful transformations with respect to efficiency and selectivity in natural product (bio)synthesis. In such polyene cyclizations, structurally highly complex carbon scaffolds are built by the controlled ring closure of linear polyenes. Thereby, multiple C,C bonds and stereocenters are simultaneously created with high precision. Structural pre-organization of the substrate carbon chain inside the active center of the enzyme is responsible for the product- and stereoselectivity of this cyclization. Here, we show that in-situ formed fluorinated-alcohol-amine supramolecular clusters serve as artificial cyclases by triggering enzyme-like reactivity and selectivity by controlling substrate conformation in solution. Because of the dynamic nature of these supramolecular assemblies, a broad range of terpenes can be produced diastereoselectively. Mechanistic studies reveal a finely balanced interplay of fluorinated solvent, catalyst, and substrate as key to establishing nature’s concept of a shape-selective polyene cyclization in organic synthesis.

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confidence: 99%

Enzyme-like polyene cyclizations catalyzed by dynamic, self-assembled, supramolecular fluoro alcohol-amine clusters

et al. 2023

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“…The C6 oxidation products represent versatile synthetic intermediates for the preparation of several complex terpenoids. As noted earlier, aldehyde 5 served as a key intermediate in Tong's synthesis of ansellone B (1), 8 but it had to be prepared from sclareolide in 17 steps. We sought to adapt several procedures 17 previously described for the conversion of sclareol to sclareolide in the corresponding modification of 9 (Scheme 1A).…”

Section: Figurementioning

confidence: 99%

“…Nevertheless, applications of C-H oxidation methodologies on the general drimane skeleton 5 have resulted exclusively in A-ring functionalization and this methodological gap has rendered the chiral pool synthesis of complex terpenoids bearing B-ring oxidation(s) inefficient (Figure 1). To illustrate, Tong and co-workers 8 reported the total synthesis of ansellone B (1) via aldehyde 5. While this intermediate could be converted to 1 in five steps, its preparation from sclareolide (4) required 17 steps comprising several indirect functional group manipulations.…”

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Remote B-Ring Oxidation of Sclareol with an Engineered P450 Facilitates Divergent Access to Complex Terpenoids

Deng

Renata

2022

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Though chiral pool synthesis is widely accepted as a powerful strategy in complex molecule synthesis, the effectiveness of the approach is intimately linked to the range of available chiral building blocks and the functional groups they possess. To date, there is still a pressing need for new remote functionalization methods that would allow the installation of useful chem-ical handles on these building blocks to enable a broader spectrum of synthetic manipulations. Herein, we report the engi-neering of a P450BM3 variant for the regioselective C–H oxidation of sclareol at C6. The synthetic utility of the resulting product was demonstrated in a formal synthesis of ansellone B and the first total synthesis of the 2,3-seco-labdane excolide B.

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Unified Asymmetric Total Syntheses of (−)‐Alotaketals A–D and (−)‐Phorbaketal A

et al. 2017

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The novel tricyclic spiroketal alotane-type sesterterpenoids showed strikingly different biological activities and potency with subtle structural alterations.A symmetric total syntheses of the tricyclic sesterterpenoids (À)-alotaketals A-D and (À)-phorbaketal Awere accomplished [29-31 steps from (À)-malic acid] in ac ollective way for the first time.T he key features of the strategy included 1) anew cascade cyclization of vinyl epoxy d-keto-alcohols to forge the common tricyclic spiroketal intermediate,2 )a late-stage allylic CÀHo xidation, and 3) olefin cross-metathesis to install the different side chains. Angewandte Chemie CommunicationsScheme 3. Synthesis of the tricyclic core 8.F or X-ray structure thermal ellipsoids shown at 40 %probability. [30] DIBAL-H = diisobutylaluminum hydride, DIPT = diisopropyl tartrate, DMSO = dimethyl sulfoxide, NHC = N-heterocyclic carbene, TBAF = tetra-n-butylammonium fluoride, TBDPS = tert-butyldiphenylsilyl, TMS = trimethylsilyl. Angewandte ChemieCommunications 9097 Scheme 4. Collective total syntheses of (À)-alotaketals A-D (1-4)a nd (À)-phorbaketalA(5). KHMDS = potassiumbis(trimethylsilyl)amide, G-II = Grubbs catalyst second generation, MeSO 2 PT = methyl 1-phenyl-1H-tetrazol-5-yl sulfone. AngewandteChemie Communications Angewandte Chemie Communications 9099

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Total Syntheses of Sesterterpenoid Ansellones A and B, and Phorbadione

Abstract: Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.

Cited by 10 publications

References 65 publications

Enzyme-like polyene cyclizations catalyzed by dynamic, self-assembled, supramolecular fluoro alcohol-amine clusters

Enzyme-like polyene cyclizations catalyzed by dynamic, self-assembled, supramolecular fluoro alcohol-amine clusters

Remote B-Ring Oxidation of Sclareol with an Engineered P450 Facilitates Divergent Access to Complex Terpenoids

Unified Asymmetric Total Syntheses of (−)‐Alotaketals A–D and (−)‐Phorbaketal A

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