Browse
Submit Data
Databases
API
Help

Dataset Information

32 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Cinchonium Betaines as Efficient Catalysts for Asymmetric Proton Transfer Catalysis: The Development of a Practical Enantioselective Isomerization of Trifluoromethyl Imines.

ABSTRACT: We have developed a new class of cinchonium betaine catalysts bearing both a base moiety and an aromatic moiety as an N-substituent of the quinuclidine motif. These cinchonium betaines were found to promote proton transfer catalysis with 1000-5000 turnovers per 24 h, thereby enabling us to realize highly efficient enantioselective isomerization of trifluoromethyl imines to provide a practical access to optically active trifluoromethylated amines.

SUBMITTER: Zhou X

PROVIDER: S-EPMC5072400 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Cinchonium Betaines as Efficient Catalysts for Asymmetric Proton Transfer Catalysis: The Development of a Practical Enantioselective Isomerization of Trifluoromethyl Imines.

Zhou Xiao X Wu Yongwei Y Deng Li L

Journal of the American Chemical Society 20160909 37

We have developed a new class of cinchonium betaine catalysts bearing both a base moiety and an aromatic moiety as an N-substituent of the quinuclidine motif. These cinchonium betaines were found to promote proton transfer catalysis with 1000-5000 turnovers per 24 h, thereby enabling us to realize highly efficient enantioselective isomerization of trifluoromethyl imines to provide a practical access to optically active trifluoromethylated amines. ...[more]

PMID: 27579574

Similar Datasets

Asymmetric synthesis of trifluoromethylated amines via catalytic enantioselective isomerization of imines.

Project description:A new approach toward the asymmetric synthesis of optically active trifluoromethylated amines was enabled by an unprecedented, highly enantioselective catalytic isomerization of trifluoromethyl imines with a new chiral organic catalyst. Not only aryl but also alkyl trifluoromethylated amines could be obtained in high enantioselectivities.

| S-EPMC3475161 | biostudies-literature

Asymmetric olefin isomerization of butenolides via proton transfer catalysis by an organic molecule.

Project description:An unprecedented enantioselective and general olefin isomerization was realized via biomimetic proton transfer catalysis with a new chiral organic catalyst. A broad range of mono- and disubstituted β,γ-unsaturated butenolides were transformed into the corresponding chiral α,β-unsaturated butenolides in high enantioselectivity and yield in the presence of as low as 0.5 mol % catalyst. Mechanistic studies have revealed the protonation as the rate-determining step.

| S-EPMC3156085 | biostudies-literature

Electronically Activated Organoboron Catalysts for Enantioselective Propargyl Addition to Trifluoromethyl Ketones.

Project description:A broadly applicable, practical, scalable, efficient and highly ?- and enantioselective method for addition of a silyl-protected propargyl moiety to trifluoromethyl ketones has been developed. Reactions, promoted by 2.0?mol?% of a catalyst that is derived in situ from a readily accessible aminophenol compound at ambient temperature, were complete after only 15?minutes at room temperature. The desired tertiary alcohols were isolated in up to 97?% yield and 98.5:1.5 enantiomeric ratio. Alkyl-, alkenyl-, alkynyl-, aryl- or heteroaryl-substituted trifluoromethyl ketones can be used. Utility is highlighted by application to a transformation that is relevant to enantioselective synthesis of BI 653048, a compound active against rheumatoid arthritis.

| S-EPMC5535737 | biostudies-literature

Asymmetric cyanation of imines via dipeptide-derived organophosphine dual-reagent catalysis.

Project description:Over the past few decades, enantioselective phosphine organocatalysis has evolved rapidly into a highly efficient catalytic strategy for a range of useful reactions. However, as restricted by the traditional catalytic modes, some important reactions, such as asymmetric Strecker-type reactions, have thus far been out of reach of this strategy. Reported herein is an application of enantioselective phosphine organocatalysis for asymmetric Strecker-type reactions, enabled by a dual-reagent catalyst system in which the key organophosphorus zwitterion intermediate, generated in situ by mixing a chiral dipeptide-derived multifunctional organophosphine with methyl acrylate, is used as a highly efficient chiral Lewis base catalyst. The high efficiency of this catalytic system is demonstrated in the asymmetric cyanation of isatin-derived ketimines and azomethine aldimines as well as in the kinetic resolution of racemic 3-substituted azomethines. Mechanistic studies provide experimental evidence for the intermediacy of the putative zwitterion and its role as a catalytically active Lewis base.

| S-EPMC5027285 | biostudies-literature

Practical and highly enantioselective synthesis of beta-alkynyl-beta-amino esters through Ag-catalyzed asymmetric mannich reactions of silylketene acetals and alkynyl imines.

Project description:[reaction: see text] A readily available iso-leucine-based phosphine ligand is used to promote Ag-catalyzed Mannich reactions between silylketene acetals and various alkynyl imines. Reactions can be effected in the presence of 5 mol % catalyst, without the need for rigorous exclusion of air, and with commercially available solvents (without purification) to afford the desired beta-alkynyl-beta-amino esters in 84-94% ee and 61-91% isolated yield.

| S-EPMC2597397 | biostudies-literature

Catalytic Asymmetric Synthesis of Trifluoromethylated ?-Amino Acids through the Umpolung Addition of Trifluoromethyl Imines to Carboxylic Acid Derivatives.

Project description:Novel cinchona alkaloid derived chiral phase-transfer catalysts enabled the highly chemo-, regio-, diastereo-, and enantioselective umpolung addition of trifluoromethyl imines to ?,?-unsaturated N-acyl pyrroles. With a catalyst loading ranging from 0.2 to 5.0?mol?%, this new catalytic asymmetric transformation provides facile and high-yielding access to highly enantiomerically enriched chiral trifluoromethylated ?-amino acids and ?-lactams.

| S-EPMC6408948 | biostudies-literature

Enantioselective construction of pyrrolidines by palladium-catalyzed asymmetric [3 + 2] cycloaddition of trimethylenemethane with imines.

Project description:A protocol for the enantioselective [3 + 2] cycloaddition of trimethylenemethane (TMM) with imines has been developed. Central to this effort were the novel phosphoramidite ligands developed in our laboratories. The conditions developed to effect an asymmetric TMM reaction using 2-trimethylsilylmethyl allyl acetate were shown to be tolerant of a wide variety of imine acceptors to provide the corresponding pyrrolidine cycloadducts with excellent yields and selectivities. Use of a bis-2-naphthyl phosphoramidite allowed the successful cycloaddition of the parent TMM with N-Boc imines, and has further permitted the reaction of substituted donors with N-tosyl aldimines and ketimines in high regio-, diastereo-, and enantioselectivity. Use of a diphenylazetidine ligand allows the complementary synthesis of the exocyclic nitrile product shown, and we demonstrate control of the regioselectivity of the product based on manipulation of the reaction parameters.

| S-EPMC3407810 | biostudies-literature

Enantioselective synthesis of α-amino ketones through palladium-catalyzed asymmetric arylation of α-keto imines.

Project description:Chiral α-amino ketones are common structural motifs in natural products and pharmaceuticals, as well as important synthons in organic synthesis. Thus, establishing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein we disclose a new catalytic asymmetric approach for the synthesis of chiral α-amino ketones through a chiral palladium-catalyzed arylation reaction of in situ generated challenging α-keto imines from previously unreported C-acyl N-sulfonyl-N,O-aminals, with arylboronic acids. The current reaction offers a straightforward approach to the asymmetric synthesis of acyclic α-amino ketones in a practical and highly stereocontrolled manner. Meanwhile, the multiple roles of the chiral Pd(ii) complex catalyst in the reaction were also reported.

| S-EPMC8966749 | biostudies-literature

Combining asymmetric catalysis with natural product functionalization through enantioselective alpha-fluorination.

Project description:An examination into the derivatization of various natural products using newly developed alpha-fluorination methodology is disclosed. An activated ketene enolate, generated from an acid chloride, is allowed to react with an electrophilic fluorine source (NFSi). Quenching the reaction with a nucleophilic natural product produces biologically relevant alpha-fluorinated carbonyl derivatives of select chemotherapeutics, antibiotics, and other pharmaceuticals.

| S-EPMC3443555 | biostudies-literature

Enantioselective rhodium-catalyzed isomerization of 4-iminocrotonates: asymmetric synthesis of a unique chiral synthon.

Project description:An enantioselective isomerization of 4-iminocrotonates catalyzed by a rhodium(I)/phosphoramidite complex is described. This reaction uses widely available amines to couple with 4-oxocrotonate to provide a convenient access to a central chiral building block in good yield and high enantioselectivity. Although the mechanism of this new transformation remains unclear, both Rh and the phosphoramidite play a central role.

| S-EPMC4986700 | 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