Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ladder polyether synthesis via epoxide-opening cascades directed by a disappearing trimethylsilyl group.

ABSTRACT: Epoxide-opening cascades offer the potential to construct complex polyether natural products expeditiously and in a manner that emulates the biogenesis proposed for these compounds. Herein we provide a full account of our development of a strategy that addresses several important challenges of such cascades. The centerpiece of the method is a trimethylsilyl (SiMe(3)) group that serves several purposes and leaves no trace of itself by the time the cascade has come to an end. The main function of the SiMe(3) group is to dictate the regioselectivity of epoxide opening. This strategy is the only general method of effecting endo-selective cascades under basic conditions.

SUBMITTER: Heffron TP

PROVIDER: S-EPMC3018858 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ladder polyether synthesis via epoxide-opening cascades directed by a disappearing trimethylsilyl group.

Heffron Timothy P TP Simpson Graham L GL Merino Estibaliz E Jamison Timothy F TF

The Journal of organic chemistry 20100401 8

Epoxide-opening cascades offer the potential to construct complex polyether natural products expeditiously and in a manner that emulates the biogenesis proposed for these compounds. Herein we provide a full account of our development of a strategy that addresses several important challenges of such cascades. The centerpiece of the method is a trimethylsilyl (SiMe(3)) group that serves several purposes and leaves no trace of itself by the time the cascade has come to an end. The main function of ...[more]

PMID: 20302314

Similar Datasets

Water overcomes methyl group directing effects in epoxide-opening cascades.

Project description:Water is an effective promoter of the endo-selective opening of trisubstituted epoxides, enabling related cascades leading to a variety of substituted ladder polyether structures. When used in conjunction with a tetrahydropyran-templated nucleophile, water can overcome the powerful electronic directing effect of a methyl substituent at either site of the epoxide, making water a uniquely versatile medium and promoter of epoxide opening.

| S-EPMC2803343 | biostudies-literature

Rhodium-catalyzed endo-selective epoxide-opening cascades: formal synthesis of (-)-brevisin.

Project description:[Rh(CO)2Cl]2 is as an effective catalyst for endo-selective cyclizations and cascades of epoxy-(E)-enoate alcohols, thus enabling the synthesis of oxepanes and oxepane-containing polyethers from di- and trisubstituted epoxides. Syntheses of the ABC and EF ring systems of (-)-brevisin via all endo-diepoxide-opening cascades using this method constitute a formal total synthesis and demonstrate the utility of this methodology in the context of the synthesis of marine ladder polyether natural products.

| S-EPMC4586266 | biostudies-literature

Epoxide-opening cascades promoted by water.

Project description:Selectivity rules in organic chemistry have been inferred largely from nonaqueous environments. In contrast, enzymes operate in water, and the chemical effect of the medium change remains only partially understood. Structural characterization of the "ladder" polyether marine natural products raised a puzzle that persisted for 20 years: Although the stereochemistry of adjacent tetrahydropyran (THP) cycles would seem to arise from a biosynthetic cascade of epoxide-opening reactions, experience in organic solvents argued consistently that such a pathway would be kinetically disfavored. We report that neutral water acts as an optimal promoter for the requisite ring-opening selectivity, once a single templating THP is appended to a chain of epoxides. This strategy offers a high-yielding route to the naturally occurring ladder core and highlights the likely importance of aqueous-medium effects in underpinning certain noteworthy enzymatic selectivities.

| S-EPMC2810534 | biostudies-literature

Total Synthesis of the Marine Ladder Polyether Gymnocin B.

Project description:Herein, we report the first total synthesis of marine ladder polyether gymnocin B (1) based on a two-phase strategy. In Phase I, inspired by the proposed biosynthesis, epoxide-opening cascades assemble 10 out of 15 cyclic ether rings making up the molecular core. In the subsequent Phase II, coalescence elevates the molecular complexity further by coupling of these subunits. Our two-phase synthetic approach significantly improved the step efficiency of the synthesis of this class of natural products.

| S-EPMC6824195 | biostudies-literature

Synthesis of cananodine by intramolecular epoxide opening.

Project description:Cananodine is a guaipyridine alkaloid with activity against liver cancer. Cananodine was synthesized using a remarkable intramolecular opening of a trisubstituted epoxide as the key step in construction of the seven-membered carbocycle of the target. The epoxide opening strategy allows all four stereoisomers of cananodine to be prepared.

| S-EPMC5722248 | biostudies-other

Total synthesis of ent-dioxepandehydrothyrsiferol via a bromonium-initiated epoxide-opening cascade.

Project description:In the first total synthesis of ent-dioxepandehydrothyrsiferol, the signature trans-anti-trans 7,7,6-fused tricyclic polyether framework was constructed in a single bromonium-initiated epoxide-opening cascade that incorporates both endo- and exo-selective epoxide openings, each directed by the substitution pattern of the epoxide (methyl groups). This study thus demonstrates the feasibility of a possible biogenesis.

| S-EPMC2760255 | biostudies-literature

Evidence that epoxide-opening cascades promoted by water are stepwise and become faster and more selective after the first cyclization.

Project description:A detailed kinetic study of the endo-selective epoxide-opening cascade reaction of a diepoxy alcohol in neutral water was undertaken using (1)H NMR spectroscopy. The observation of monoepoxide intermediates resulting from initial endo and exo cyclization indicated that the cascade proceeds via a stepwise mechanism rather than through a concerted one. Independent synthesis and cyclization of these monoepoxide intermediates demonstrated that they are chemically and kinetically competent intermediates in the cascade. Analysis of each step of the reaction revealed that both the rate and regioselectivity of cyclization improve as the cascade reaction proceeds. In the second step, cyclization of an epoxy alcohol substrate templated by a fused diad of two tetrahydropyran rings proceeds with exceptionally high regioselectivity (endo:exo = 19:1), the highest we have measured in the opening of a simple trans-disubstituted epoxide. The origins of these observations are discussed.

| S-EPMC3084897 | biostudies-literature

The Disappearing Director: The Case of Directed N-Arylation via a Removable Hydroxyl Group.

Project description:A facile and broadly applicable method for the regiospecific N-arylation of benzotriazoles is reported. Copper-mediated reactions of diverse 1-hydroxy-1H-benzotriazoles with aryl boronic acids lead to 1-aryl-1H-benzotriazole 3-oxides. A N1-OH → N3 prototropy in the 1-hydroxy-1H-benzotriazoles is plausibly the underlying basis, where the tautomer is captured by the boronic acid, leading to C-N (not C-O) bond formation. Because the N-O bond in amine N-oxides and 1-hydroxy-1H-benzotriazoles can be easily reduced by diboron reagents such as (pinB)2 and B2(OH)4, exposure of the 1-aryl-1H-benzotriazole 3-oxides to B2(OH)4 then leads to facile reduction of the N-O bond resulting in diverse, regiospecifically-arylated benzotriazoles. Thus, the N-hydroxyl group in 1-hydroxy-1H-benzotriazoles acts as a disposable arylation director.

| S-EPMC6294448 | biostudies-literature

Fluorinated ?-Lactones and Poly(?-hydroxyalkanoate)s: Synthesis via Epoxide Carbonylation and Ring-Opening Polymerization.

Project description:Efficient and mild reaction conditions were developed for the catalytic carbonylation of fluorinated epoxides to their corresponding ?-lactones. Six new lactones with fluorinated side chains were prepared in high isolated yields. These lactones were polymerized to form a series of new poly(?-hydroxyalkanoate)s with fluorinated side chains, and their properties were examined with respect to their hydrocarbon analogs. Finally, copolymerizations were performed with fluorinated lactones and ?-butyrolactone, which resulted in tapered copolymers rather than the expected random copolymers.

| S-EPMC2583445 | biostudies-literature

Total syntheses of the squalene-derived halogenated polyethers ent-dioxepandehydrothyrsiferol and armatol A via bromonium- and Lewis acid-initiated epoxide-opening cascades.

Project description:Herein we describe in full our investigations leading to the first total syntheses of ent-dioxepandehydrothyrsiferol and armatol A. Discovery of a bromonium-initiated epoxide-opening cascade enabled novel tactics for constructing key fragments found in both natural products and have led us to revise the proposed biogeneses. Other common features found in the routes include convergent fragment coupling strategies to assemble the natural products' backbones and the use of epoxide-opening cascades for rapid constructions of the fused polyether subunits. Through de novo synthesis of armatol A, we elucidate the absolute and relative configuration of this natural product.

| S-EPMC3713853 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data