Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Enantioselective Total Synthesis of Andrographolide and 14-Hydroxy-Colladonin: Carbonyl Reductive Coupling and trans-Decalin Formation by Hydrogen Transfer.

ABSTRACT: An enantioselective total synthesis of the labdane diterpene andrographolide, the bitter principle of the herb Andrographis paniculata (known as "King of Bitters"), was accomplished in 14 steps (LLS). Key transformations include iridium-catalyzed carbonyl reductive coupling to form the quaternary C4 stereocenter, diastereoselective alkene reduction to establish the trans-decalin ring, and carbonylative lactonization to install the α-alkylidene-β-hydroxy-γ-butyrolactone.

SUBMITTER: Yang L

PROVIDER: S-EPMC7920188 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Enantioselective Total Synthesis of Andrographolide and 14-Hydroxy-Colladonin: Carbonyl Reductive Coupling and trans-Decalin Formation by Hydrogen Transfer.

Yang Lin L Wurm Thomas T Sharma Poudel Binit B Krische Michael J MJ

Angewandte Chemie (International ed. in English) 20201015 51

An enantioselective total synthesis of the labdane diterpene andrographolide, the bitter principle of the herb Andrographis paniculata (known as "King of Bitters"), was accomplished in 14 steps (LLS). Key transformations include iridium-catalyzed carbonyl reductive coupling to form the quaternary C4 stereocenter, diastereoselective alkene reduction to establish the trans-decalin ring, and carbonylative lactonization to install the α-alkylidene-β-hydroxy-γ-butyrolactone. ...[more]

PMID: 32896046

Similar Datasets

Direct Conversion of Primary Alcohols to 1,2-Amino Alcohols: Enantioselective Iridium-Catalyzed Carbonyl Reductive Coupling of Phthalimido-Allene via Hydrogen Auto-Transfer.

Project description:The first catalytic enantioselective carbonyl (α-amino)allylations are described. Phthalimido-allene 1 and primary alcohols 2a-2z, 2a'-2c' engage in hydrogen auto-transfer-mediated carbonyl reductive coupling by way of (α-amino)allyliridium-aldehyde pairs to form vicinal amino alcohols 3a-3z, 3a'-3c' with high levels of regio-, anti-diastereo-, and enantioselectivity. Reaction progress kinetic analysis and isotopic labeling studies corroborate a catalytic cycle involving turnover-limiting alcohol dehydrogenation followed by rapid allene hydrometalation.

| S-EPMC6739137 | biostudies-literature

Enantioselective reductive multicomponent coupling reactions between isatins and aldehydes.

Project description:A metal-free stereoselective reductive coupling reaction between isatins and aldehydes is reported. The reaction relies on commercial diethyl phosphite (∼€70 kg-1) as the stoichiometric reductant. Base-catalyzed Pudovik addition and phosphonate/phosphate rearrangement achieved polarity inversion on the isatin, and the derived carbanions were trapped by aldehydes with subsequent dialkoxyphosphinyl migration. Chiral iminophosphoranes were used as basic catalysts to achieve high diastereo- and enantioselectivities with excellent yields.

| S-EPMC4618493 | biostudies-literature

Ruthenium(ii)-catalyzed olefination via carbonyl reductive cross-coupling.

Project description:Natural availability of carbonyl groups offers reductive carbonyl coupling tremendous synthetic potential for efficient olefin synthesis, yet the catalytic carbonyl cross-coupling remains largely elusive. We report herein such a reaction, mediated by hydrazine under ruthenium(ii) catalysis. This method enables facile and selective cross-couplings of two unsymmetrical carbonyl compounds in either an intermolecular or intramolecular fashion. Moreover, this chemistry accommodates a variety of substrates, proceeds under mild reaction conditions with good functional group tolerance, and generates stoichiometric benign byproducts. Importantly, the coexistence of KO t Bu and bidentate phosphine dmpe is vital to this transformation.

| S-EPMC5855968 | biostudies-literature

Enantioselective iridium-catalyzed carbonyl isoprenylation via alcohol-mediated hydrogen transfer.

Project description:Highly enantioselective iridium catalyzed carbonyl (2-vinyl)allylation or "isoprenylation" is achieved via hydrogen auto-transfer or 2-propanol-mediated reductive coupling from primary alcohol or aldehyde reactants, respectively. Using this method, asymmetric total syntheses of the terpenoid natural products (+)-ipsenol and (+)-ipsdienol were achieved.

| S-EPMC6339811 | biostudies-literature

Enantioselective desymmetrization via carbonyl-directed catalytic asymmetric hydroboration and Suzuki-Miyaura cross-coupling.

Project description:The rhodium-catalyzed enantioselective desymmetrization of symmetric ?,?-unsaturated amides via carbonyl-directed catalytic asymmetric hydroboration (directed CAHB) affords chiral secondary organoboronates with up to 98% ee. The chiral ?-borylated products undergo palladium-catalyzed Suzuki-Miyaura cross-coupling via the trifluoroborate salt with stereoretention.

| S-EPMC4385711 | biostudies-other

Cyclometalated Iridium-PhanePhos Complexes Are Active Catalysts in Enantioselective Allene-Fluoral Reductive Coupling and Related Alcohol-Mediated Carbonyl Additions That Form Acyclic Quaternary Carbon Stereocenters.

Project description:Iridium complexes modified by the chiral phosphine ligand PhanePhos catalyze the 2-propanol-mediated reductive coupling of diverse 1,1-disubstituted allenes 1a-1u with fluoral hydrate 2a to form CF3-substituted secondary alcohols 3a-3u that incorporate acyclic quaternary carbon-containing stereodiads. By exploiting concentration-dependent stereoselectivity effects related to the interconversion of kinetic ( Z)- and thermodynamic ( E)-σ-allyliridium isomers, adducts 3a-3u are formed with complete levels of branched regioselectivity and high levels of anti-diastereo- and enantioselectivity. The utility of this method for construction of CF3-oxetanes and CF3-azetidines is illustrated by the formation of 4a and 6a, respectively. Studies of the reaction mechanism aimed at illuminating the singular effectiveness of PhanePhos as a supporting ligand in this and related transformations have led to the identification of a chromatographically stable cyclometalated iridium-( R)-PhanePhos complex, Ir-PP-I, that is catalytically competent for allene-fluoral reductive coupling and previously reported transfer hydrogenative C-C couplings of dienes or CF3-allenes with methanol. Deuterium labeling studies, reaction progress kinetic analysis (RPKA) and computational studies corroborate a catalytic mechanism involving rapid allene hydrometalation followed by turnover-limiting carbonyl addition. A computationally determined stereochemical model shows that the ortho-CH2 group of the cyclometalated iridium-PhanePhos complex plays a key role in directing diastereo- and enantioselectivity. The collective data provide key insights into the structural-interactional features of allyliridium complexes required to enforce nucleophilic character, which should inform the design of related cyclometalated catalysts for umpoled allylation.

| S-EPMC6423978 | biostudies-literature

Enantioselective Ruthenium-BINAP-Catalyzed Carbonyl Reductive Coupling of Alkoxyallenes: Convergent Construction of syn-sec,tert-Diols via (Z)-σ-Allylmetal Intermediates.

Project description:The first catalytic enantioselective ruthenium-catalyzed carbonyl reductive couplings of allene pronucleophiles is described. Using an iodide-modified ruthenium-BINAP-catalyst and O-benzhydryl alkoxyallene 1a, carbonyl (α-alkoxy)allylation occurs from the alcohol or aldehyde oxidation level to form enantiomerically enriched syn-sec,tert-diols. Internal chelation directs intervention of (Z)-σ-alkoxyallylruthenium isomers, which engage in stereospecific carbonyl addition.

| S-EPMC8299538 | biostudies-literature

Catalytic Enantioselective Allylations of Acetylenic Aldehydes via 2-Propanol-Mediated Reductive Coupling.

Project description:Cyclometalated π-allyliridium C,O-benzoates modified by ( S)-SEGPHOS or ( S)-Cl,OMe-BIPHEP catalyze enantioselective 2-propanol-mediated reductive couplings of diverse nonmetallic allyl pronucleophiles with the acetylenic aldehyde TIPSC≡CCHO. Absolute stereochemistries of the resulting secondary homoallylic-propargylic alcohols were assigned using Rychnovsky's competing enantioselective conversion method.

| S-EPMC6205292 | biostudies-literature

Enantioselective CuH-Catalyzed Reductive Coupling of Aryl Alkenes and Activated Carboxylic Acids.

Project description:A new method for the enantioselective reductive coupling of aryl alkenes with activated carboxylic acid derivatives via copper hydride catalysis is described. Dual catalytic cycles are proposed, with a relatively fast enantioselective hydroacylation cycle followed by a slower diastereoselective ketone reduction cycle. Symmetrical aryl carboxyclic anhydrides provide access to enantioenriched ?-substituted ketones or alcohols with excellent stereoselectivity and functional group tolerance.

| S-EPMC4866599 | biostudies-literature

Nickel-Catalyzed Enantioselective Electrochemical Reductive Cross-Coupling of Aryl Aziridines with Alkenyl Bromides.

Project description:An electrochemically driven nickel-catalyzed enantioselective reductive cross-coupling of aryl aziridines with alkenyl bromides has been developed, affording enantioenriched β-aryl homoallylic amines with excellent E-selectivity. This electroreductive strategy proceeds in the absence of heterogeneous metal reductants and sacrificial anodes by employing constant current electrolysis in an undivided cell with triethylamine as a terminal reductant. The reaction features mild conditions, remarkable stereocontrol, broad substrate scope, and excellent functional group compatibility, which was illustrated by the late-stage functionalization of bioactive molecules. Mechanistic studies indicate that this transformation conforms with a stereoconvergent mechanism in which the aziridine is activated through a nucleophilic halide ring-opening process.

| S-EPMC10037331 | 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