A tellurium transposition route to allylic alcohols: overcoming some limitations of the Sharpless-Katsuki asymmetric epoxidation

Dittmer, Donald C.; Discordia, Robert P.; Zhang, Yanzhi; Murphy, Christian; Kumar, Ankesh; Pepito, Aurora S.; Wang, Yue-Sheng

doi:10.1021/jo00055a029

Cited by 53 publications

(30 citation statements)

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confidence: 83%

“…Fractionation of an ethanolic extract of A. sceptrum afforded the diterpenoid dialdehyde 2 [7], its diethyl acetal 3, the sesquiterpene (+)-(S)-nerolidol (4) [8], [9], and coronarin B (5) [10]. The 1 H-and 13 C-NMR spectra of 2, 4 and 5 were in agreement with those published in the literature [7], [8], [9], [10]. While both enantiomers of 2 have previously been isolated [7], [11], the dialdehyde 2 obtained from A. sceptrum was dextrorotatory, [a] D 25 : +138 (c 0.2 CHCl 3 ) or +148 (c 0.2, EtOH), reported +168…”

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confidence: 99%

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Antiplasmodial Activity of Labdanes from Aframomum latifolium and Aframomum sceptrum

Duker-Eshun¹,

Jaroszewski²,

Asomaning³

et al. 2002

Planta med

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Bioguided fractionation of extracts of Aframomum latifolium and A. sceptrum (Zingiberaceae) resulted in isolation of (+)-( S)-nerolidol and seven labdanes, coronarin B, galanal A and B, galanolactone, ( E)-8beta,17-epoxylabd-12-ene-15,16-dial, (+)-( E)-labda-8(17), 12-diene-15,16-dial and its diethyl acetal, the latter being presumably an isolation artefact. The labdanes show a modest in vitro activity against a chloroquine-sensitive Plasmodium falciparum strain.

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supporting

confidence: 83%

mentioning

confidence: 99%

Antiplasmodial Activity of Labdanes from Aframomum latifolium and Aframomum sceptrum

Duker-Eshun¹,

Jaroszewski²,

Asomaning³

et al. 2002

Planta med

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“…Would catalysts be found that would functionalize the allylic alkene 20 , or other olefins of 1 ? Oxidation of 1 with (+) or (−)-DIPT/Ti(O i -Pr) 4 under the conditions of Sharpless has been reported over the years to deliver 3 with excellent selectivity (82–95% ee; Fig 1c) 21,22,23,24,25,26 . However, we lacked a clear structure-based hypothesis for how peptide-based catalysts might achieve our goals.…”

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confidence: 99%

Combinatorial evolution of site- and enantioselective catalysts for polyene epoxidation

2012

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Selectivity in the catalytic functionalization of complex molecules is a major challenge in chemical synthesis. The problem is magnified when there are several possible stereochemical outcomes and when similar functional groups occur repeatedly within the same molecule. Selective polyene oxidation provides an archetypical example of this challenge. Historically, enzymatic catalysis provided the only precedents. Although nonenzymatic catalysts are now known that meet some of these challenges, a comprehensive solution has remained elusive. Here, we describe low molecular weight, peptide-based catalysts discovered through a combinatorial synthesis and screening protocol that exhibit site- and enantioselective oxidation of certain positions of various isoprenols. This diversity-based approach, which exhibits features remiscent of the directed evolution of enzymes, delivers catalysts that compare favourably to the state-of-the-art for asymmertric oxidation of these compounds. Moreover, the approach culminated in catalysts that exhibit alternate site-selectivity in comparison to previously described oxidation catalysts.

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“…(3R,6E)-nerolidol was prepared in analogy to the published synthesis of (S) enantiomer [26]. (2R,3R)-Epoxyfarnesol (300 mg, 1.3 mmol) was dissolved in DCM (10 mL) and cooled to 0 °C.…”

Section: H Nmr (See Supplementary Materialmentioning

confidence: 99%

(3R,6E)-nerolidol, a fertility-related volatile secreted by the queens of higher termites (Termitidae: Syntermitinae)

Havlíčková

Dolejšová

Tichý

et al. 2019

Zeitschrift Für Naturforschung C

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The queens of advanced social insects maintain their reproductive monopoly by using exocrine chemicals. The chemistry of these “queen pheromones” in termites is poorly known. We show that primary queens of four higher termites from the subfamily Syntermitinae (Embiratermes neotenicus, Silvestritermes heyeri, Labiotermes labralis, and Cyrilliotermes angulariceps) emit significant amounts of the sesquiterpene alcohol (E)-nerolidol. It is the dominant analyte in queen body washes; it is present on the surface of eggs, but absent in kings, workers, and soldiers. In E. neotenicus, it is also produced by replacement neotenic queens, in quantities correlated with their fertility. Using newly synthesised (3R,6E)-nerolidol, we demonstrate that the queens of this species produce only the (R) enantiomer. It is distributed over the surface of their abdomen, in internal tissues, and in the haemolymph, as well as in the headspace of the queens. Both (R) and (S) enantiomers are perceived by the antennae of E. neotenicus workers. The naturally occurring (R) enantiomer elicited a significantly larger antennal response, but it did not show any behavioural effect. In spite of technical difficulties encountered in long-term experiments with the studied species, (3R,6E)-nerolidol remains among eventual candidates for the role in queen fertility signalling.

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A tellurium transposition route to allylic alcohols: overcoming some limitations of the Sharpless-Katsuki asymmetric epoxidation

Cited by 53 publications

References 0 publications

Antiplasmodial Activity of Labdanes from Aframomum latifolium and Aframomum sceptrum

Antiplasmodial Activity of Labdanes from Aframomum latifolium and Aframomum sceptrum

Combinatorial evolution of site- and enantioselective catalysts for polyene epoxidation

(3R,6E)-nerolidol, a fertility-related volatile secreted by the queens of higher termites (Termitidae: Syntermitinae)

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