A Concise Approach to Paxilline Indole Diterpenes

George, David T.; Kuenstner, Eric J.; Пронин, С. В.

doi:10.1021/jacs.5b11129

Cited by 106 publications

(68 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…to 11.3 (entries 4–5). 11 Fortunately, the 25-fold less-expensive catalyst Mn(acac) 3 (Sigma) performs reasonably well in the reaction with 6 , forming 10 in 89 % yield, d.r. 7.2 (Table 4, entry 2), whereas this catalyst performs poorly with PhSiH 3 .…”

Section: Resultsmentioning

confidence: 99%

“…The solvent versatility also allowed the novel radical-polar crossover methods as the Pronin lab has already shown in a recent synthesis of emindole SB. 11 We also include data to suggest that HAT does not occur from the ligand, which is an alternative hypothesis for HAT reactions involving the dimethylglyoxime (dmg) ligand. Further isotope labeling experiments revealed preferential deuterium incorporation during the HAT along with hydrogen scrambling from the substrate.…”

Section: Discussionmentioning

confidence: 99%

“…11 A key step in this work consists of a radical-polar crossover cyclization based on radical conjugate addition followed by intramolecular aldol cyclization (Scheme 3). Reactions of 7 as well as other analogs using phenylsilane produced 8a / 8b in low yield and with multiple byproducts, but the reaction was significantly improved by use of Ph( i -PrO)SiH 2 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ph(i-PrO)SiH₂: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

2016

View full text Add to dashboard Cite

We report the discovery of an outstanding reductant for metal-catalyzed radical hydrofunctionalization reactions. Observations of unexpected silane solvolysis distributions in the HAT-initiated hydrogenation of alkenes reveal that phenylsilane is not the kinetically preferred reductant in many of these transformations. Instead, isopropoxy(phenyl)silane forms under the reactions conditions, suggesting that alcohols function as important silane ligands to promote the formation of metal hydrides. Study of its reactivity showed that isopropoxy(phenyl)silane is an exceptionally efficient stoichiometric reductant and it is now possible to significantly decrease catalyst loadings, lower reaction temperatures, broaden functional group tolerance and use diverse, aprotic solvents in iron- and manganese-catalyzed hydrofunctionalizations. As representative examples, we have improved the yields and rates of alkene reduction, hydration, hydroamination and conjugate addition. Discovery of this broadly applicable, chemoselective and solvent-versatile reagent should allow an easier interface with existing radical reactions. Finally, isotope-labeling experiments rule out the alternative hypothesis of hydrogen atom transfer from a redox-active beta-diketonate ligand in the HAT step. Instead, initial HAT from a metal-hydride to directly generate a carbon-centered radical appears to be the most reasonable hypothesis.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ph(i-PrO)SiH₂: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

2016

View full text Add to dashboard Cite

show abstract

“…[31] [32] Pronin's group recently applied iron-catalyzed HAT cyclization/ aldol addition sequence to establish the eastern portion of indole diterpenoid, (-)-nodulisporic acid C (Scheme 20). [32,39] The synthesis began with the copper-catalyzed asymmetric conjugate addition to 86 using the JosiPhos derivative SL-J015-1 to prepare the silyl-enol ether 87 in 95 % yield and 73 % ee. This silyl enol ether underwent an addition catalyzed by indium (III) bromide to the TBS-protected pent-4-yn-1-ol, [40] and the following acid work-up provided access to 88 containing a quaternary stereocenter.…”

Section: Mukayiama's Hydration For the Diastereoselective Introductiomentioning

confidence: 99%

Recent Progress in Steroid Synthesis Triggered by the Emergence of New Catalytic Methods

et al. 2020

View full text Add to dashboard Cite

The rich biology associated with steroids dictates a growing demand for the new synthetic strategies that would improve the access to natural and unnatural representatives of this family. The recent advances in the field of catalysis have greatly impacted the field of natural product synthesis including the synthesis of steroids. This article provides a short overview of the recent progress in the synthesis of steroids that was enabled by the advances in catalysis.

show abstract

“…Most of the terpenes produced by fungi have various biological functions. Terpene include commercially fascinating compounds due to their properties, such as paxilline an indole diterpene, gibberelic acid, a pentacyclic diterpene plant growth hormone and trichothecenes a sesquiterpene mycotoxin [2,3].…”

Section: Introductionmentioning

confidence: 99%

ISOLATION OF TWO BOTRYANES FROM Hypoxylon rickii AND IDENTIFICATION OF THE ENCODING GENES

Alwi

Rosandy

Bakar³

et al. 2017

MJAS

View full text Add to dashboard Cite

10-oxodehydrobotrydial (1) and 4β-Acetoxy-9β,10β,15α-trihydroxyprobotrydial (2) have been isolated from Hypoxylon rickii mycelia extract. Compound 2 is probably an intermediate of botrydial, which is a known sesquiterpene phytotoxin. Cluster Omega and Artemis software analysis suggested that HRT6, a possible botrydial-like gene cluster with four genes shows more than 50% similarities compared to Botrytis cinerea botrydial gene cluster, BcBOT. A comparison between proposed 4β-Acetoxy-9β,10β,15α-trihydroxyprobotrydial (2) producing pathway and BcBOT proposed pathway shows compatible function of each gene prediction. Further confirmation using RNA gene knock-outs is on-going. Keywords:Hypoxylon rickii, botryane, terpene synthase Abstrak 10-oksodehidrobotridial (1) dan 4β-Asetoksi-9β,10β,15α-trihidroksiprobotridial (2) telah dipencilkan dari ekstrak miselia Hypoxylon rickii. Sebatian 2 dijangkakan sebagai sebatian perantara dalam pembentukkan botridial iaitu sejenis fitotoksin sesquiterpena. Penggunaan dua perisian Cluster Omega dan Artemis telah berjaya mengenalpasti gen kelompok yang berkemungkinan dari H. rickii sebagai HRT6 dengan empat gen menunjukkan persamaan lebih daripada 50% berbanding gen kelompok Botrytis cinerea, BcBOT. Perbandingan antara dengan cadangan laluan biosintesis 4β-Asetoksi-9β,10β,15α-trihidroksiprobotridial (2) dengan BcBOT menunjukkan persamaan fungsi -fungsi gen. Pengesahan lanjut menggunakan RNA (mendiamkan gen) sedang dijalankan.

show abstract

A Concise Approach to Paxilline Indole Diterpenes

Cited by 106 publications

References 72 publications

Ph(i-PrO)SiH₂: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

Ph(i-PrO)SiH₂: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

Recent Progress in Steroid Synthesis Triggered by the Emergence of New Catalytic Methods

ISOLATION OF TWO BOTRYANES FROM Hypoxylon rickii AND IDENTIFICATION OF THE ENCODING GENES

Contact Info

Product

Resources

About

A Concise Approach to Paxilline Indole Diterpenes

Cited by 106 publications

References 72 publications

Ph(i-PrO)SiH2: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

Ph(i-PrO)SiH2: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

Recent Progress in Steroid Synthesis Triggered by the Emergence of New Catalytic Methods

ISOLATION OF TWO BOTRYANES FROM Hypoxylon rickii AND IDENTIFICATION OF THE ENCODING GENES

Contact Info

Product

Resources

About

Ph(i-PrO)SiH₂: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers

Ph(i-PrO)SiH₂: An Exceptional Reductant for Metal-Catalyzed Hydrogen Atom Transfers