Browse
Submit Data
Databases
API
Help

Dataset Information

14 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

(Salen)Mn(iii)-catalyzed chemoselective acylazidation of olefins.

ABSTRACT: We describe a (salen)Mn(iii)-catalyzed three-component reaction of aldehydes, olefins, and sodium azide for the installation of two useful groups (C[double bond, length as m-dash]O and N3) into the double bond. Traditionally, (salen)Mn(iii) in conjunction with iodosobenzene is a classical catalysis system for epoxidation of olefins. Owing to the highly competitive oxygenation approaches, it is a true challenge to establish a distinct strategy for the exploration of new olefin transformations based on this (salen)Mn(iii) catalysis system. Herein, the key to this (salen)Mn(iii)-catalyzed acylazidation of olefins was the rational application of the distinct reactivity of oxomanganese(v) species which is capable of abstracting a hydrogen atom from a substrate C-H bond. This chemoselective reaction occurred in a precisely designed reaction sequence and tolerates complex molecular structures.

SUBMITTER: Zhang L

PROVIDER: S-EPMC6053955 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

(Salen)Mn(iii)-catalyzed chemoselective acylazidation of olefins.

Zhang Liang L Liu Shuya S Zhao Zhiguo Z Su Hongmei H Hao Jingcheng J Wang Yao Y

Chemical science 20180619 28

We describe a (salen)Mn(iii)-catalyzed three-component reaction of aldehydes, olefins, and sodium azide for the installation of two useful groups (C[double bond, length as m-dash]O and N<sub>3</sub>) into the double bond. Traditionally, (salen)Mn(iii) in conjunction with iodosobenzene is a classical catalysis system for epoxidation of olefins. Owing to the highly competitive oxygenation approaches, it is a true challenge to establish a distinct strategy for the exploration of new olefin transfor ...[more]

PMID: 30090296

Similar Datasets

(Salen)Mn(III) Catalyzed Asymmetric Epoxidation Reactions by Hydrogen Peroxide in Water: A Green Protocol.

Project description:Enantioselective epoxidation reactions of some chosen reactive alkenes by a chiral Mn(III) salen catalyst were performed in H?O employing H?O? as oxidant and diethyltetradecylamine N-oxide (AOE-14) as surfactant. This procedure represents an environmentally benign protocol which leads to e.e. values ranging from good to excellent (up to 95%).

| S-EPMC4964487 | biostudies-literature

Mechanism of the enantioselective oxidation of racemic secondary alcohols catalyzed by chiral Mn(III)-salen complexes.

Project description:The experiments described here clarify the mechanism and origin of the enantioselectivity of the oxidation of racemic secondary alcohols catalyzed by chiral Mn(III)-salen complexes using HOBr, Br(2)/H(2)O/KOAc or PhI(OAc)(2)/H(2)O/KBr as a stoichiometric oxidant. Key points of the proposed pathway include (1) the formation of a Mn(V)-salen dibromide, (2) its subsequent reaction with the alcohol to give an alkoxy-Mn(V) species, and (3) carbonyl-forming elimination to produce the ketone via a highly organized transition state with intramolecular transfer of hydrogen from carbon to an oxygen of the salen ligand.

| S-EPMC2945693 | biostudies-literature

Oligomeric (Salen)Mn(III) Complexes Featuring Tartrate Linkers Immobilized over Layered Double Hydroxide for Catalytically Asymmetric Epoxidation of Unfunctionalized Olefins.

Project description:A series of oligomeric (salen)Mn(III) complexes featuring tartrate linkers were prepared and immobilized over layered double hydroxide, and then used as catalysts for asymmetric epoxidation of unfunctionalized olefins. Comprehensive characterizations including 1H NMR, FT-IR, UV-Vis, elemental analysis, GPC, and ICP-AES were used to illustrate structures of oligomeric (salen)Mn(III) complexes, while powdered XRD, nitrogen physisorption, together with XPS studies provided further details to detect structures of heterogeneous catalysts. Interestingly, scanning electron microscopy found an interesting morphology change during modification of layered supporting material. Catalytic experiments indicated that configuration of major epoxide products was determined by salen chirality more than that of tartrate linker, but enantioselectivity (e.e. values) could be enhanced when tartrate and salen showed identical chiral configurations. Furthermore, the (R,R)-salen moieties linked with (R,R)-tartrate spacers usually offered higher enantioselectivity compared to other combinations. Lastly, Zn(II)/Al(III) layered double hydroxide played as a rigid supporting material in catalysis, showing positive chiral induction and high recycling potential in catalytic reactions.

| S-EPMC7672564 | biostudies-literature

Epoxidation of unfunctionalized olefins by Mn(salen) catalyst using organic peracids as oxygen source: a theoretical study.

Project description:The mechanism and origin of asymmetric induction in the Mn(III)(salen)-catalyzed epoxidation by peracetic acid have been elucidated by the density functional [Becke three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional (B3LYP)] method in two different regimes: with and without an axial ligand. The acylperoxo complexes of Mn(II,III,IV) in cisON cisNO and trans geometrical configurations cannot compete with the catalyst-free Prilezhaev epoxidation. Instead, oxo species perform epoxidation following the O-O bond cleavage in the acylperoxo complexes. The epoxidation may proceed in a concerted and/or radical-mediated stepwise manner. The actual mechanism of the epoxidation depends on the electronic and oxidation state of the oxo species and the nature of the axial ligand. The olefin can approach the reactive MnO fragment of both cis and trans-l-isomers of the plain oxo species along multiple distinct directions: native approaches. The native approaches are used to rationalize the inversion of the absolute configuration of the product epoxide due to the axial ligand.

| S-EPMC395978 | biostudies-literature

Development and mechanistic investigation of the manganese(iii) salen-catalyzed dehydrogenation of alcohols.

Project description:The first example of a manganese(iii) catalyst for the acceptorless dehydrogenation of alcohols is presented. N,N'-Bis(salicylidene)-1,2-cyclohexanediaminomanganese(iii) chloride (2) has been shown to catalyze the direct synthesis of imines from a variety of alcohols and amines with the liberation of hydrogen gas. The mechanism has been investigated experimentally with labelled substrates and theoretically with DFT calculations. The results indicate a metal-ligand bifunctional pathway in which both imine groups in the salen ligand are first reduced to form a manganese(iii) amido complex as the catalytically active species. Dehydrogenation of the alcohol then takes place by a stepwise outer-sphere hydrogen transfer generating a manganese(iii) salan hydride from which hydrogen gas is released.

| S-EPMC6349018 | biostudies-literature

Rh(III)-Catalyzed Cyclopropanation of Unactivated Olefins Initiated by C-H Activation.

Project description:We have developed a Rh(III)-catalyzed cyclopropanation of unactivated olefins initiated by an alkenyl C-H activation. A variety of 1,1-disubstituted olefins undergo efficient cyclopropanation with a slight excess of alkene stoichiometry. A series of mechanistic interrogations implicate a metal-carbene as an intermediate.

| S-EPMC7428168 | biostudies-literature

Enantioselective intramolecular openings of oxetanes catalyzed by (salen)Co(III) complexes: access to enantioenriched tetrahydrofurans.

Project description:The catalytic enantioselective intramolecular ring-opening of oxetanes with alcohols is catalyzed by (salen)Co(III) complexes. Either a monomeric or oligomeric catalyst can be used successfully in this transformation, providing 3-substituted tetrahydrofurans in both high yield and enantioselectivity. This methodology extends the range of electrophiles that can be activated toward highly enantioselective addition reactions by (salen)metal catalysts to an important new class.

| S-EPMC2765541 | biostudies-literature

Iridium-catalyzed (Z)-trialkylsilylation of terminal olefins.

Project description:A complex of commercial [Ir(OMe)(cod)](2) and 4,4-di-tert-butyl-2,2-bipyridine (dtbpy) catalyzes the Z-selective, dehydrative silylation of terminal alkenes, but not 1,2-disubstituted alkenes, with triethylsilane or benzyldimethylsilane in THF at 40 degrees C. Yields and Z-stereoselectivity were significantly improved by 2-norbornene, in contrast with other sacrificial alkenes. The reaction is compatible with many functional groups including epoxides, ketones, amides, alcohols, esters, halides, ketals, and silanes. alpha,beta-Unsaturated esters were unreactive. The reaction probably proceeds through a Heck-type mechanism.

| S-EPMC2830331 | biostudies-other

Iron-catalyzed aminohydroxylation of olefins.

Project description:We have discovered that N-sulfonyl oxaziridines react with a broad range of olefins in the presence of iron salts to afford 1,3-oxazolidines. This process provides access to 1,2-aminoalcohols with the opposite sense of regioselectivity produced from the copper-catalyzed oxyamination previously reported by our laboratories. Thus, either regioisomeric form of 1,2-aminoalcohols can easily be obtained from the reaction of oxaziridines with olefins, and the sense of regioselectivity can be controlled by the appropriate choice of inexpensive, nontoxic, first-row transition-metal catalyst.

| S-EPMC2857537 | biostudies-literature

Mechanistic basis for high stereoselectivity and broad substrate scope in the (salen)Co(III)-catalyzed hydrolytic kinetic resolution.

Project description:In the (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides, the rate- and stereoselectivity-determining epoxide ring-opening step occurs by a cooperative bimetallic mechanism with one Co(III) complex acting as a Lewis acid and another serving to deliver the hydroxide nucleophile. In this paper, we analyze the basis for the extraordinarily high stereoselectivity and broad substrate scope observed in the HKR. We demonstrate that the stereochemistry of each of the two (salen)Co(III) complexes in the rate-determining transition structure is important for productive catalysis: a measurable rate of hydrolysis occurs only if the absolute stereochemistry of each of these (salen)Co(III) complexes is the same. Experimental and computational studies provide strong evidence that stereochemical communication in the HKR is mediated by the stepped conformation of the salen ligand, and not the shape of the chiral diamine backbone of the ligand. A detailed computational analysis reveals that the epoxide binds the Lewis acidic Co(III) complex in a well-defined geometry imposed by stereoelectronic rather than steric effects. This insight serves as the basis of a complete stereochemical and transition structure model that sheds light on the reasons for the broad substrate generality of the HKR.

| S-EPMC3875305 | 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