Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Enantioselective addition of boronates to chromene acetals catalyzed by a chiral Bronsted acid/Lewis acid system.

ABSTRACT:

SUBMITTER: Moquist PN

PROVIDER: S-EPMC3035997 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Enantioselective addition of boronates to chromene acetals catalyzed by a chiral Brønsted acid/Lewis acid system.

Moquist Philip N PN Kodama Tomohiro T Schaus Scott E SE

Angewandte Chemie (International ed. in English) 20100901 39

PMID: 20721997

Similar Datasets

Bronsted Acid/Lewis Acid Cooperatively Catalyzed Addition of Diazoester to 2<i>H</i>-chromene Acetals.

Project description:A novel Brønsted acid/Lewis acid dual catalyst system has been developed to promote an efficient C-C bond formation between a range of oxocarbenium precursors derived from chromene acetals and ethyl diazoacetate. The reaction proceeds under mild conditions and is tolerant of common functionalized 2H-chromene and isochromene acetals. In addition, an asymmetric variant of diazoacetate addition towards 2H-chromene acetal is described. Continued investigations include the further optimization of asymmetric induction towards the formation of diazo ester substituted 2H-chromene.

| S-EPMC4233145 | biostudies-literature

Enantioselective addition of boronates to acyl imines catalyzed by chiral biphenols.

Project description:On the big screen: A chiral biphenol catalyst screening protocol was developed for the rapid identification of enantioselective nucleophilic boronate reactions with acyl imines (see scheme). The approach successfully identified a unique catalyst for the reaction of aryl, vinyl, and alkynyl boronates. Mechanistic studies demonstrate boronate ligand exchange with the catalyst is necessary for activation towards nucleophilic addition.

| S-EPMC2819183 | biostudies-literature

Enantioselective synthesis of 1,2-dihydronaphthalene-1-carbaldehydes by addition of boronates to isochromene acetals catalyzed by tartaric acid.

Project description:Tartaric acid is an ideal asymmetric catalyst as it is abundant, cheap, and environmentally friendly. (+)-Tartaric acid was found to catalyze a novel enantioselective [4 + 2] cycloaddition of isochromene acetals and vinylboronates. A variety of substituted isochromene acetals were tolerated, furnishing the desired dihydronaphthalenes and dihydrobenzofluorene products in good yields. High enantiomeric ratios (up to 98.5:1.5) and excellent diastereoselectivities (all >99:1) were observed employing 10 mol % of (+)-tartaric acid as the catalyst, in combination with 5 mol % of Ho(OTf)3.

| S-EPMC4666678 | biostudies-literature

Enantioselective bromocycloetherification by Lewis base/chiral Bronsted acid cooperative catalysis.

Project description:A binary catalyst system for the enantioselective bromocycloetherification of 5-arylpentenols is described. The combination of an achiral Lewis base and a chiral Brønsted acid affords good enantioselectivities for the cyclization of Z configured 5-arylpentenols to form bromomethyltetrahydrofurans. The constitutional site selectivity is highly dependent upon the aromatic substituent and the configuration of the double bond.

| S-EPMC3238797 | biostudies-literature

Enantioselective addition of boronates to o-quinone methides catalyzed by chiral biphenols.

Project description:Chiral biphenols were found to catalyze the enantioselective asymmetric addition of aryl- or alkenylboronates to o-quinone methides. Substituted 2-styryl phenols were obtained in good yields (up to 95%) with high enantiomeric ratios (up to 98:2) in the presence of 10 mol % 3,3'-Br(2)-BINOL. A two-step synthesis of (S)-4-methoxydalbergione in good yield and selectivity was achieved.

| S-EPMC4655814 | biostudies-literature

Enantioselective Nazarov cyclization of indole enones cooperatively catalyzed by Lewis acids and chiral Bronsted acids.

Project description:Enantioselective control of the chirality of a tertiary ?-carbon in the products of a Nazarov cyclization of enones is challenging because the reaction involves an enantioselective proton transfer process. We herein report the use of cooperative catalysis using Lewis acids and chiral Brønsted acids to control the stereochemistry of the tertiary ?-carbon in the products of this reaction. Specifically, with ZnCl2 and a chiral spiro phosphoric acid as catalysts, we realized the first enantioselective construction of cyclopenta[b]indoles with chiral tertiary ?-carbons via Nazarov cyclization of indole enone substrates with only one coordinating site. Mechanistic studies revealed that the chiral spiro phosphoric acid acts as a multifunctional catalyst: it co-catalyzes the cyclization of the dienone and enantioselectively catalyzes a proton transfer reaction of the enol intermediate. This new strategy of enantioselective control by means of cooperative catalysis may show utility for other challenging asymmetric cyclization reactions.

| S-EPMC5633839 | biostudies-other

Unconventional Bifunctional Lewis-Bronsted Acid Activation Mode in Bicyclic Guanidine-Catalyzed Conjugate Addition Reactions.

Project description:DFT calculations have demonstrated that the unconventional bifunctional Brønsted-Lewis acid activation mode is generally applicable to a range of nucleophilic conjugate additions catalyzed by bicyclic guanidine catalysts. It competes readily with the conventional bifunctional Brønsted acid mode of activation. The optimal pro-nucleophiles for this unconventional bifunctional activation are acidic substrates with low pKa, while the best electrophiles are flexible 1,4-diamide and 1,4-diester conjugated systems.

| S-EPMC6331857 | biostudies-other

Development and mechanism of an enantioselective bromocycloetherification reaction via Lewis base/chiral Bronsted acid cooperative catalysis.

Project description:The development of a binary catalyst system for bromocycloetherification, consisting of an achiral Lewis base and a chiral Brønsted acid, is described in detail. The results of preliminary kinetic studies are also presented.

| S-EPMC4676414 | biostudies-literature

Chiral Pentacarboxycyclopentadiene-Based Bronsted Acid-Catalyzed Enantioselective Desymmetrization of Meso-Epoxides by 2-Mercaptobenzothiazoles.

Project description:Enantioselective desymmetrization of meso-epoxides by 2-mercaptobenzothiazoles was realized by using the pentacarboxycyclopentadiene-based chiral Brønsted acid in combination of N-isopropylaniline as amine additive to give up to 90.5:9.5 er of the ring opening products.

| S-EPMC6644688 | biostudies-literature

Enantioenriched 1,4-Benzoxazepines via Chiral Bronsted Acid-Catalyzed Enantioselective Desymmetrization of 3-Substituted Oxetanes.

Project description:Herein, we present a highly enantioselective desymmetrization of 3-substituted oxetanes enabled by a confined chiral phosphoric acid. This metal-free process allows effective access to chiral seven-membered 1,4-benzoxazepines with a high degree of enantiocontrol, under mild reaction conditions. The developed synthetic strategy tolerates a broad substrate scope and demonstrates its synthetic utility in various enantioselective product transformations, thus proving its effectiveness in diverse scenarios.

| S-EPMC10729023 | 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