Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Chiral aminophosphines derived from hydroxyproline and their application in allene-imine [4?+?2] annulation.

ABSTRACT: A robust synthetic route from L-hydroxyproline (L-Hyp) to phosphines has established an expandable library of six chiral aminophosphines, which were then applied to the phosphine-catalyzed [4?+?2] allene-imine annulation. The enantioinduction in the annulations-induced by a purely steric effect-were moderate (up to 57% ee). A switch of the reaction site from the ?- to the ?'-carbon atom of the allenoate was observed during the annulations performed using sterically demanding chiral phosphines.

SUBMITTER: Khong SN

PROVIDER: S-EPMC6599608 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Chiral aminophosphines derived from hydroxyproline and their application in allene-imine [4 + 2] annulation.

Khong San N SN Xie Changmin C Wang Xinyi X Tan Hao H Kwon Ohyun O

The Journal of antibiotics 20190402 6

A robust synthetic route from L-hydroxyproline (L-Hyp) to phosphines has established an expandable library of six chiral aminophosphines, which were then applied to the phosphine-catalyzed [4 + 2] allene-imine annulation. The enantioinduction in the annulations-induced by a purely steric effect-were moderate (up to 57% ee). A switch of the reaction site from the γ- to the β'-carbon atom of the allenoate was observed during the annulations performed using sterically demanding chiral phosphines. ...[more]

PMID: 30940911

Similar Datasets

Total synthesis of (±)-hirsutine: application of phosphine-catalyzed imine-allene [4 + 2] annulation.

Project description:The total synthesis of the indole alkaloid hirsutine has been achieved, with a key step being the application of our phosphine-catalyzed [4 + 2] annulation of an imine with ethyl α-methylallenoate. From commercially available indole-2-carboxaldehyde, the target was synthesized in 14 steps and 6.7% overall yield.

| S-EPMC3439149 | biostudies-literature

Carvone-Derived P-Stereogenic Phosphines: Design, Synthesis, and Use in Allene-Imine [3 + 2] Annulation.

Project description:We have prepared a previously unreported family of P-stereogenic [2.2.1] bicyclic chiral phosphines through straightforward syntheses starting from the natural product carvone. This design rationale prompted the development of an unforeseen C-dealkenylation reaction. We have applied these organocatalysts in the asymmetric syntheses of a bevy of pyrrolines, obtained in high yields and enantioselectivities, including a biologically active small molecule, efsevin.

| S-EPMC6208446 | biostudies-literature

Chiral allene-containing phosphines in asymmetric catalysis.

Project description:We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic acids to α-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals that one olefin of the allene can coordinate to transition metals, generating bi- and tridentate ligands.

| S-EPMC3216402 | biostudies-literature

Traceless chiral auxiliaries for the allene ether Nazarov cyclization.

Project description:The key stereochemical factors that determine transfer of asymmetry from the chiral auxiliary to the cyclopentenone in the allene ether version of the Nazarov reaction have been elucidated. On the basis of the new insights into the mechanism, two highly effective chiral auxiliaries were designed and prepared.

| S-EPMC2674073 | biostudies-literature

Crystal structures of four chiral imine-substituted thio-phene derivatives.

Project description:A series of thio-phenes substituted in positions 2 and 5 by imine groups have been synthesized using a solvent-free approach, and their crystal structures determined. The substituents are chiral groups, and the expected absolute configuration for each mol-ecule was confirmed by refinement of the Flack parameter. The compounds are 2,5-bis-[(S)-(+)-(1,2,3,4-tetra-hydro-naphthalen-1-yl)imino]-thio-phene, C26H26N2S, (I), 2,5-bis-{[(R)-(-)-1-(4-meth-oxy-phen-yl)eth-yl]imino-meth-yl}thio-phene, C24H26N2O2S, (II), 2,5-bis-{[(R)-(-)-1-(4-fluoro-phen-yl)eth-yl]imino-meth-yl}thio-phene, C22H20F2N2S, (III), and 2,5-bis-{[(S)-(+)-1-(4-chloro-phen-yl)eth-yl]imino-meth-yl}thio-phene, C22H20Cl2N2S, (IV). A common feature of all four mol-ecules is the presence of twofold symmetry. For (I), which crystallizes in the triclinic space group P1, this symmetry is non-crystallographic, but for (II) in C2 and the isomorphous structures (III) and (IV) that crystallize in P21212, the twofold symmetry is crystallographically imposed with one half of each mol-ecule in the asymmetric unit. The comparable mol-ecular symmetry in the four structures is also reflected in similar packing, with mol-ecules aggregated to form chains through weak C-H⋯S inter-actions.

| S-EPMC4778840 | biostudies-literature

Stereoselectivity control in Rh-catalyzed β-OH elimination for chiral allene formation.

Project description:Stereoselectivity control and understanding in the metal-catalyzed reactions are fundamental issues in catalysis. Here we report sterically controlled rhodium-catalyzed SN2'-type substitution reactions of optically active tertiary propargylic alcohols with arylmetallic species affording the non-readily available enantioenriched tetrasubstituted allenes via either exclusive syn- or anti-β-OH elimination, respectively, under two sets of different reaction parameters. Detailed mechanistic experiments and density functional theory (DFT) studies reveal that the exclusive anti-Rh(I)-OH elimination is dictated by the simultaneous aid of in situ generated boric acid and ambient water, which act as the shuttle in the hydroxy relay to facilitate the Rh(I)-OH elimination process via a unique ten-membered cyclic transition state (anti-TS2_u). By contrast, the syn-Rh(III)-OH elimination in C-H bond activation-based allenylation reaction is controlled by a four-membered cyclic transition state (syn-TS3) due to the steric surroundings around the Rh(III) center preventing the approach of the other assisting molecules. Under the guidance of these mechanistic understandings, a stereodivergent protocol to construct the enantiomer of optically active tetrasubstituted allenes from the same starting materials is successfully developed.

| S-EPMC10651921 | biostudies-literature

Torquoselective ring closures of chiral amido trienes derived from allenamides. A tandem allene isomerization-pericyclic ring-closure-intramolecular Diels-Alder cycloaddition.

Project description:A new torquoselective ring-closure of chiral amide-substituted 1,3,5-hexatrienes and its application in tandem with [4 + 2] cycloaddition are described. The trienes were derived via either a 1,3-H or 1,3-H-1,7-H shift of alpha-substituted allenamides, and the entire sequence through the [4 + 2] cycloaddition could be in tandem from allenamides.

| S-EPMC2862010 | biostudies-literature

Enantioselective [4+2] Annulation to the Concise Synthesis of Chiral Dihydrocarbazoles.

Project description:A highly efficient phosphine-catalyzed enantioselective [4 + 2] annulation of allenoates with 3-nitroindoles or 3-nitrobenzothiophenes has been developed. The protocol represents a unique dearomatization-aromatization process to access functionalized dihydrocarbazoles or dihydrodibenzothiophenes with high optical purity (up to 97% ee) under mild reaction conditions. The synthetic utility of the highly enantioselective [4 + 2] annulation enables a concise synthesis of analgesic agent.

| S-EPMC6995259 | biostudies-literature

Chiral phosphine-mediated intramolecular [3 + 2] annulation: enhanced enantioselectivity by achiral Bronsted acid.

Project description:Enantioselective intramolecular [3 + 2] annulation of chalcones bearing an allene moiety has been successfully developed. The reaction was effectively promoted by amino acid-derived phosphines, in combination with achiral Brønsted acids. Dihydrocoumarin architectures were constructed in high yields and with excellent enantiomeric excesses. Theoretical studies via DFT calculations revealed that the hydrogen bonding network induced by achiral Brønsted acids/chiral phosphines could more efficiently distinguish between two enantioselective pathways, thus leading to enhanced enantioselectivity.

| S-EPMC5618691 | biostudies-other

Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes.

Project description:When Boc-L-Val-OH was used as a ligand for the enantioselective Pd(II)-catalyzed annulation of N,N-substituted aminomethyl ferrocene derivatives with diarylethynes, ferrocenes with planar chirality could be achieved with excellent enantioselectivity (up to 99% ee).

| S-EPMC3778326 | 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