Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A Protocol for Direct Stereospecific Amination of Primary, Secondary, and Tertiary Alkylboronic Esters.

ABSTRACT: The direct, stereospecific amination of alkylboronic and borinic esters can be conducted by treatment of the organoboron compound with methoxyamine and potassium tert-butoxide. In addition to being stereospecific, this process also enables the direct amination of tertiary boronic esters in an efficient fashion.

SUBMITTER: Edelstein EK

PROVIDER: S-EPMC6322687 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

A Protocol for Direct Stereospecific Amination of Primary, Secondary, and Tertiary Alkylboronic Esters.

Edelstein Emma K EK Grote Andrea C AC Palkowitz Maximilian D MD Morken James P JP

Synlett : accounts and rapid communications in synthetic organic chemistry 20180620 13

The direct, stereospecific amination of alkylboronic and borinic esters can be conducted by treatment of the organoboron compound with methoxyamine and potassium <i>tert</i>-butoxide. In addition to being stereospecific, this process also enables the direct amination of tertiary boronic esters in an efficient fashion. ...[more]

PMID: 30631220

Similar Datasets

Stereospecific Transformations of Alkylboronic Esters Enabled by Direct Boron-to-Zinc Transmetalation.

Project description:Chiral secondary organoboronic esters, when activated with t-butyllithium, are shown to undergo efficient stereoretentive transmetalation with either zinc acetate or zinc chloride. This reaction provides chiral secondary alkylzinc reagents that are configurationally stable under practical experimental conditions. The organozinc compounds were found to engage in stereospecific reactions with difluorocarbene, catalytic cross-couplings with palladium-based catalysts, and trifluoromethylation with a copper(III) complex. Mechanistic and computational studies shed light on the inner workings of the transmetalation event.

| S-EPMC10407644 | biostudies-literature

Copper-Catalyzed Stereospecific Transformations of Alkylboronic Esters.

Project description:Copper-catalyzed stereospecific cross-couplings of boronic esters are reported. Boron "ate" complexes derived from pinacol boronic esters and tert-butyl lithium undergo stereospecific transmetalation to copper cyanide, followed by coupling with alkynyl bromides, allyl halides, propargylic halides, β-haloenones, hydroxylamine esters, and acyl chlorides. Through this simple transformation, commercially available inexpensive compounds can be employed to convert primary and secondary alkylboronic esters to a wide array of synthetically useful compounds.

| S-EPMC10436227 | biostudies-literature

Direct stereospecific amination of alkyl and aryl pinacol boronates.

Project description:The direct amination of alkyl and aryl pinacol boronates is accomplished with lithiated methoxyamine. This reaction directly provides aliphatic and aromatic amines, stereospecifically, and without preactivation of the boronate substrate.

| S-EPMC3481838 | biostudies-literature

Enantiospecific Alkynylation of Alkylboronic Esters.

Project description:Enantioenriched secondary and tertiary alkyl pinacolboronic esters undergo enantiospecific deborylative alkynylation through a Zweifel-type alkenylation followed by a 1,2-elimination reaction. The process involves use of ?-lithio vinyl bromide or vinyl carbamate species, for which application to Zweifel-type reactions has not previously been explored. The resulting functionalized 1,1-disubstituted alkenes undergo facile base-mediated elimination to generate terminal alkyne products in high yield and excellent levels of enantiospecificity over a wide range of pinacolboronic ester substrates. Furthermore, along with terminal alkynes, internal and silyl-protected alkynes can be formed by simply introducing a suitable carbon- or silicon-based electrophile after the base-mediated 1,2-elimination reaction.

| S-EPMC4804747 | biostudies-literature

Substrate Plasticity Enables Group-Selective Transmetalation: Catalytic Stereospecific Cross-Couplings of Tertiary Boronic Esters.

Project description:Activation of enantiomerically enriched tertiary alkylboronic esters with adamantyllithium generated in situ enables stereoretentive boron-to-copper transmetalation. The resulting alkylcopper species can undergo cross-coupling reactions with an array of electrophiles to furnish synthetically useful compounds bearing quaternary stereocenters. DFT calculations of the transmetalation process provide insights for reactivity and selectivity.

| S-EPMC10924285 | biostudies-literature

An enzymatic platform for the asymmetric amination of primary, secondary and tertiary C(sp<sup>3</sup>)-H bonds.

Project description:The ability to selectively functionalize ubiquitous C-H bonds streamlines the construction of complex molecular architectures from easily available precursors. Here we report enzyme catalysts derived from a cytochrome P450 that use a nitrene transfer mechanism for the enantioselective amination of primary, secondary and tertiary C(sp3)-H bonds. These fully genetically encoded enzymes are produced and function in bacteria, where they can be optimized by directed evolution for a broad spectrum of enantioselective C(sp3)-H amination reactions. These catalysts can aminate a variety of benzylic, allylic and aliphatic C-H bonds in excellent enantioselectivity with access to either antipode of product. Enantioselective amination of primary C(sp3)-H bonds in substrates that bear geminal dimethyl substituents furnished chiral amines that feature a quaternary stereocentre. Moreover, these enzymes enabled the enantioconvergent transformation of racemic substrates that possess a tertiary C(sp3)-H bond to afford products that bear a tetrasubstituted stereocentre, a process that has eluded small-molecule catalysts. Further engineering allowed for the enantioselective construction of methyl-ethyl stereocentres, which is notoriously challenging in asymmetric catalysis.

| S-EPMC6998391 | biostudies-literature

Direct Primary Amination of Alkylmetals with NH-Oxaziridine.

Project description:A method for the primary electrophilic amination of primary, secondary, and tertiary organometallic substrates from a bench-stable NH-oxaziridine reagent is described. This facile and highly chemoselective transformation occurs at ambient temperature and without transition metal catalysts or purification by column chromatography to provide alkylamine products in a single step. Density functional theory (DFT) calculations revealed that, despite the basicity of alkylmetals, the direct NH-transfer pathway is favored over proton and O-transfer.

| S-EPMC7803087 | biostudies-literature

Non-Deprotonative Primary and Secondary Amination of (Hetero)Arylmetals.

Project description:Herein we disclose a novel method for the facile transfer of primary (-NH2) and secondary amino groups (-NHR) to heteroaryl- as well as arylcuprates at low temperature without the need for precious metal catalysts, ligands, excess reagents, protecting and/or directing groups. This one-pot transformation allows unprecedented functional group tolerance and it is well-suited for the amination of electron-rich, electron-deficient as well as structurally complex (hetero)arylmetals. In some of the cases, only catalytic amounts of a copper(I) salt is required.

| S-EPMC5348115 | biostudies-literature

Radical-mediated direct C-H amination of arenes with secondary amines.

Project description:Aryl dialkyl amines, valuable subunits of a wide range of effect chemicals, are accessed by intramolecular amination of aromatic C-H bonds employing UV photolysis of N-chloroamines. The reactions show good functional group tolerance and allow access to a range of fused and bridged polycyclic structures. The homogeneous reaction conditions allow for the one-pot conversion of secondary amines to their arylated derivatives. Experimental and theoretical evidence supports the involvement of electrophilic aminium radicals which react via direct ortho-attack on the arene.

| S-EPMC6115623 | biostudies-literature

Secondary amines as coupling partners in direct catalytic asymmetric reductive amination.

Project description:The secondary amine participating asymmetric reductive amination remains an unsolved problem in organic synthesis. Here we show for the first time that secondary amines are capable of effectively serving as N-sources in direct asymmetric reductive amination to afford corresponding tertiary chiral amines with the help of a selected additive set under mild conditions (0-25 °C). The applied chiral phosphoramidite ligands are readily prepared from BINOL and easily modified. Compared with common tertiary chiral amine synthetic methods, this procedure is much more concise and scalable, as exemplified by the facile synthesis of rivastigmine and N-methyl-1-phenylethanamine.

| S-EPMC6482873 | 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