Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Catalytic enantioselective total syntheses of bakkenolides I, J, and S: application of a carbene-catalyzed desymmetrization.

ABSTRACT: A general strategy for the catalytic asymmetric syntheses of the bakkenolides is reported. The key bond-forming step involves an N-heterocyclic carbene catalyzed desymmetrization of a 1,3-diketone to form three new bonds in one step with excellent enantio- and diastereoselectivity. This intramolecular reaction allows direct access to the hydrindane core of the bakkenolide family and enables a facile synthesis of these natural products.

SUBMITTER: Phillips EM

PROVIDER: S-EPMC2884059 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Catalytic enantioselective total syntheses of bakkenolides I, J, and S: application of a carbene-catalyzed desymmetrization.

Phillips Eric M EM Roberts John M JM Scheidt Karl A KA

Organic letters 20100601 12

A general strategy for the catalytic asymmetric syntheses of the bakkenolides is reported. The key bond-forming step involves an N-heterocyclic carbene catalyzed desymmetrization of a 1,3-diketone to form three new bonds in one step with excellent enantio- and diastereoselectivity. This intramolecular reaction allows direct access to the hydrindane core of the bakkenolide family and enables a facile synthesis of these natural products. ...[more]

PMID: 20469924

Similar Datasets

Dual catalytic enantioselective desymmetrization of allene-tethered cyclohexanones.

Project description:The construction of enantioenriched azabicyclo[3.3.1]nonan-6-one heterocycles via an enantioselective desymmetrization of allene-linked cyclohexanones, enabled through a dual catalytic system, that provides synchronous activation of the cyclohexanone with a chiral prolinamide and the allene with a copper(i) co-catalyst to deliver the stereodefined bicyclic core, is described. Successful application to oxygen analogues was also achieved, thereby providing a new enantioselective synthetic entry to architecturally complex bicyclic ethereal frameworks. The mechanistic pathway and the origin of enantio- and diastereoselectivities has been uncovered using density functional theory (DFT) calculations.

| S-EPMC8159440 | biostudies-literature

Enantioselective Desymmetrization of Methylenedianilines via Enzyme-Catalyzed Remote Halogenation.

Project description:Extensive effort has been devoted to engineering flavin-dependent halogenases (FDHs) with improved stability, expanded substrate scope, and altered regioselectivity. Here, we show that variants of rebeccamycin halogenase (RebH) catalyze enantioselective desymmetrization of methylenedianilines via halogenation of these substrates distal to their pro-stereogenic center. Structure-guided engineering was used to increase the conversion and selectivity of these reactions, and the synthetic utility of the halogenated products was shown via conversion of to a chiral α-substituted indole. These results constitute the first reported examples of asymmetric catalysis by FDHs.

| S-EPMC5898188 | biostudies-literature

Enantioselective Syntheses of (-)-Alloyohimbane and (-)-Yohimbane by an Efficient Enzymatic Desymmetrization Process.

Project description:Enantioselective syntheses of (-)-alloyohimbane and (-)-yohimbane was accomplished in a convergent manner. The key step involved a modified mild protocol for the enantioselective enzymatic desymmetrization of meso-diacetate. The protocol provided convenient access to an optically active monoacetate in multi-gram scale in high enantiomeric purity. This monoacetate was converted to (-)-alloyohimbane. Reductive amination of the derived aldehyde causes the isomerization leading to the trans-product and allows the synthesis of (-)-yohimbane.

| S-EPMC5526648 | biostudies-literature

Enantioselective formal total syntheses of didehydrostemofoline and isodidehydrostemofoline through a catalytic dipolar cycloaddition cascade.

Project description:Sweet to the core: Enantioselective formal total syntheses of the title compounds were accomplished in 24 steps from 2-deoxy-D-ribose. The synthesis features a novel cascade of reactions culminating in an intramolecular dipolar cycloaddition to form the tricyclic core of the stemofoline alkaloids from an acyclic diazo imine intermediate.

| S-EPMC3541778 | biostudies-literature

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation.

Project description:Pd-catalyzed enantioselective alkylation in conjunction with further synthetic elaboration enables the formal total syntheses of a number of "classic" natural product target molecules. This publication highlights recent methods for setting quaternary and tetrasubstituted tertiary carbon stereocenters to address the synthetic hurdles encountered over many decades across multiple compound classes spanning carbohydrate derivatives, terpenes, and alkaloids. These enantioselective methods will impact both academic and industrial settings, where the synthesis of stereogenic quaternary carbons is a continuing challenge.

| S-EPMC4222294 | biostudies-literature

Enantioselective Total Syntheses of (+)-Fendleridine and (+)-Acetylaspidoalbidine.

Project description:Enantioselective syntheses of hexacyclic aspidoalbidine alkaloids (+)-fendleridine (2) and (+)-acetylaspidoalbidine (3) are described. These syntheses feature an asymmetric decarboxylative allylation and photocyclization of a highly substituted enaminone. Also, the synthesis highlights the formation of a C19-hemiaminal ether via a reduction/condensation/intramolecular cyclization cascade with the C21-alcohol. The present synthesis provides convenient access to the aspidoalbidine hexacyclic alkaloid family in an efficient manner.

| S-EPMC6594018 | biostudies-literature

Enantioselective total syntheses of (-)-taiwaniaquinone H and (-)-taiwaniaquinol B by iridium-catalyzed borylation and palladium-catalyzed asymmetric α-arylation.

Project description:We report a concise, enantioselective total synthesis of (-)-taiwaniaquinone H and the first enantioselective total synthesis of (-)-taiwaniaquinol B by a route that includes asymmetric palladium-catalyzed α-arylation of a ketone with an aryl bromide that was generated by sterically controlled halogenation via iridium-catalyzed C-H borylation. This asymmetric α-arylation creates the benzylic quaternary stereogenic center present in the taiwaniaquinoids. The synthesis was completed efficiently by developing a Lewis acid-promoted cascade to construct the [6,5,6] tricyclic core of an intermediate common to the synthesis of a number of taiwaniaquinoids. Through the preparation of these compounds, we demonstrate the utility of constructing benzylic quaternary stereogenic centers, even those lacking a carbonyl group in the α-position, by asymmetric α-arylation.

| S-EPMC3042318 | biostudies-literature

Enantioselective Cyclopropanation Catalyzed by Gold(I)-Carbene Complexes.

Project description:The formation of polysubstituted cyclopropane derivatives in the gold(I)-catalyzed reaction of olefins and propargylic esters is a potentially useful transformation to generate diversity, therefore any method in which its stereoselectivity could be controlled is of significant interest. We prepared and tested a series of chiral gold(I)-carbene complexes as a catalyst in this transformation. With a systematic optimization of the reaction conditions, we were able to achieve high enantioselectivity in the test reaction while the cis:trans selectivity of the transformation was independent of the catalyst. Using the optimized conditions, we reacted a series of various olefins and acetylene derivatives to find that, although the reactions proceeded smoothly and the products were usually isolated in good yield and with good to exclusive cis selectivity, the observed enantioselectivity varied greatly and was sometimes moderate at best. We were unable to establish any structure-property relationship, which suggests that for any given reagent combination, one has to identify individually the best catalyst.

| S-EPMC9501563 | biostudies-literature

Light-Driven Enantioselective Carbene-Catalyzed Radical-Radical Coupling.

Project description:An enantioselective carbene-catalyzed radical-radical coupling of acyl imidazoles and racemic Hantzsch esters is disclosed. This method involves the coupling of an N-heterocyclic carbene-derived ketyl radical and a secondary sp3 -carbon radical and allows access to chiral α-aryl aliphatic ketones in moderate-to-good yields and enantioselectivities without any competitive epimerization. The utility of this protocol is highlighted by the late-stage functionalization of various pharmaceutical compounds and is further demonstrated by the transformation of the enantioenriched products to biologically relevant molecules. Computational investigations reveal the N-heterocyclic carbene controls the double-facial selectivity of the ketyl radical and the alkyl radicals, respectively.

| S-EPMC10841513 | biostudies-literature

Dual Nickel- and Photoredox-Catalyzed Enantioselective Desymmetrization of Cyclic meso-Anhydrides.

Project description:The enantioselective desymmetrization of cyclic meso-anhydrides with benzyl trifluoroborates under nickel-photoredox catalysis is described. The reaction tolerates a variety of sterically and electronically different trifluoroborates, as well as structurally unique cyclic anhydrides. The trans isomer of the keto-acid products is also observed at varying levels dependent on the trifluoroborate identity and relative catalyst loading. A mechanism involving decarbonylation and Ni-C bond homolysis of a NiII adduct is proposed. This feature allows access to a trans keto-acid as the major product in high enantioselectivity from a cis meso anhydride.

| S-EPMC5510164 | 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