Browse
Submit Data
Databases
API
Help

Dataset Information

42 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ni- and Pd-catalyzed synthesis of substituted and functionalized allylic boronates.

ABSTRACT: Two highly efficient and convenient methods for the synthesis of functionalized and substituted allylic boronates are described. In one procedure, readily available allylic acetates are converted to allylic boronates catalyzed by Ni/PCy(3) or Ni/PPh(3) complexes with high levels of stereoselectivity and in good yields. Alternatively, the borylation can be accomplished with commercially available Pd catalysts [e.g., Pd(2)(dba)(3), PdCl(2), Pd/C], starting with easily accessed allylic halides.

SUBMITTER: Zhang P

PROVIDER: S-EPMC3322416 | biostudies-literature | 2012 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ni- and Pd-catalyzed synthesis of substituted and functionalized allylic boronates.

Zhang Ping P Roundtree Ian A IA Morken James P JP

Organic letters 20120229 6

Two highly efficient and convenient methods for the synthesis of functionalized and substituted allylic boronates are described. In one procedure, readily available allylic acetates are converted to allylic boronates catalyzed by Ni/PCy(3) or Ni/PPh(3) complexes with high levels of stereoselectivity and in good yields. Alternatively, the borylation can be accomplished with commercially available Pd catalysts [e.g., Pd(2)(dba)(3), PdCl(2), Pd/C], starting with easily accessed allylic halides. ...[more]

PMID: 22375950

Similar Datasets

Pd-catalyzed synthesis of allylic silanes from allylic ethers.

Project description:Allylic phenyl ethers serve as electrophiles toward Pd(0) en route to a variety of allylic silanes. The reactions can be run at room temperature in water as the only medium using micellar catalysis.

| S-EPMC2804976 | biostudies-literature

Synthesis of α-substituted cyclic boronates <i>via</i> titanium-catalyzed cyclization of vinyl boronates with dihaloalkanes.

Project description:Cyclic boronates are versatile synthons for organic synthesis and for introducing ring systems into bioactive molecules. Existing synthetic methods have narrow substrate scope and the synthesis of α-substituted cyclic boronates is still elusive. Furthermore, no general method for synthesizing cyclic boronates with different ring sizes and hetero atom containing rings is available. Herein, we present a new and general synthetic method for synthesizing α-substituted cyclic boronates. Our approach has the advantage of using earth-abundant Ti as the catalyst and readily available dihaloalkanes, such as dichloromethane, as the reactant. Cyclic boronates that are otherwise difficult to access, such as α-substituted cyclic boronates with three-, four-, five-, and six-membered rings, heteroatom-containing rings, and cyclic boronates with spiro rings, are readily obtained.

| S-EPMC11913033 | biostudies-literature

Synthesis of Alkenyl Boronates from Epoxides with Di-[B(pin)]-methane via Pd-Catalyzed Dehydroboration.

Project description:A practical and broadly applicable catalytic method for the synthesis of (E)-alkenylborons is presented. Reactions are promoted by [Pd(Cl)(η3-C3H5)]2 and proceed by the dehydroboration of cyclic borates. Through the use of epoxides and readily available di-B(pin)-methane (pin = pinacolato), a range of allylic alcohol-containing alkenyl boronates, including those that contain a tertiary alcohol, may be prepared in up to 75% yield and >20:1 E/Z.

| S-EPMC5937844 | biostudies-literature

Allylic alcohol synthesis by Ni-catalyzed direct and selective coupling of alkynes and methanol.

Project description:Methanol is an abundant and renewable chemical raw material, but its use as a C1 source in C-C bond coupling reactions still constitutes a big challenge, and the known methods are limited to the use of expensive and noble metal catalysts such as Ru, Rh and Ir. We herein report nickel-catalyzed direct coupling of alkynes and methanol, providing direct access to valuable allylic alcohols in good yields and excellent chemo- and regioselectivity. The approach features a broad substrate scope and high atom-, step- and redox-economy. Moreover, this method was successfully extended to the synthesis of [5,6]-bicyclic hemiacetals through a cascade cyclization reaction of alkynones and methanol.

| S-EPMC8278963 | biostudies-literature

Multimetallic Ni- and Pd-Catalyzed Cross-Electrophile Coupling To Form Highly Substituted 1,3-Dienes.

Project description:The synthesis of highly substituted 1,3-dienes from the coupling of vinyl bromides with vinyl triflates is reported for the first time. The coupling is catalyzed by a combination of (5,5'-bis(trifluoromethyl)-2,2'-bipyridine)NiBr2 and (1,3-bis(diphenylphosphino)propane)PdCl2 in the presence of a zinc reductant. This method affords tetra- and penta-substituted 1,3-dienes that would otherwise be difficult to access and tolerates electron-rich and -poor substituents, heterocycles, an aryl bromide, and a pinacol boronate ester. Mechanistically, the reaction appears to proceed by an unusual zinc-mediated transfer of a vinyl group between the nickel and palladium centers.

| S-EPMC5821523 | biostudies-literature

Alpha-selective Ni-catalyzed hydroalumination of aryl- and alkyl-substituted terminal alkynes: practical syntheses of internal vinyl aluminums, halides, or boronates.

Project description:A method for Ni-catalyzed hydroalumination of terminal alkynes, leading to the formation of alpha-vinylaluminum isomers efficiently (>98% conv in 2-12 h) and with high selectivity (95% to >98% alpha), is described. Catalytic alpha-selective hydroalumination reactions proceed in the presence of a reagent (diisobutylaluminum hydride; dibal-H) and 3.0 mol % metal complex (Ni(dppp)Cl(2)) that are commercially available and inexpensive. Under the same conditions, but with Ni(PPh(3))(2)Cl(2), hydroalumination becomes highly beta-selective, and, unlike uncatalyzed transformations with dibal-H, generates little or no alkynylaluminum byproducts. All hydrometalation reactions are reliable, operationally simple, and practical and afford an assortment of vinylaluminums that are otherwise not easily accessible. The derived alpha-vinyl halides and boronates can be synthesized through direct treatment with the appropriate electrophiles [e.g., Br(2) and methoxy(pinacolato)boron, respectively]. Ni-catalyzed hydroaluminations can be performed with as little as 0.1 mol % catalyst and on gram scale with equally high efficiency and selectivity.

| S-EPMC2921967 | biostudies-literature

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches.

Project description:We present the synthesis and the spin switching efficiencies of Ni(II)-porphyrins substituted with azopyridines as covalently attached photoswitchable ligands. The molecules are designed in such a way that the azopyridines coordinate to the Ni ion if the azo unit is in cis configuration. For steric reasons no intramolecular coordination is possible if the azopyridine unit adopts the trans configuration. Photoisomerization of the azo unit between cis and trans is achieved upon irradiation with 505 nm (trans→cis) and 435 nm (cis→trans). Concurrently with the isomerization and coordination/decoordination, the spin state of the Ni ion switches between singlet (low-spin) and triplet (high-spin). Previous studies have shown that the spin switching efficiency is strongly dependent on the solvent and on the substituent at the 4-position of the pyridine unit. We now introduced thiol, disulfide, thioethers, nitrile and carboxylic acid groups and investigated their spin switching efficiency.

| S-EPMC7590622 | biostudies-literature

Unusual Enantiodivergence in Chiral Bronsted Acid-Catalyzed Asymmetric Allylation with β-Alkenyl Allylic Boronates.

Project description:We report herein a rare example of enantiodivergent aldehyde addition with β-alkenyl allylic boronates via chiral Brønsted acid catalysis. 2,6-Di-9-anthracenyl-substituted chiral phosphoric acid-catalyzed asymmetric allylation using β-vinyl substituted allylic boronate gave alcohols with R absolute configuration. The sense of asymmetric induction of the catalyst in these reactions is opposite to those in prior reports. Moreover, in the presence of the same acid catalyst, the reactions with β-2-propenyl substituted allylic boronate generated homoallylic alcohol products with S absolute configuration. Unusual substrate-catalyst C-H⋅⋅⋅π interactions in the favoured reaction transition state were identified as the origins of observed enantiodivergence through DFT computational studies.

| S-EPMC10319447 | biostudies-literature

NHC-Ni catalyzed 1,3- and 1,4-diastereodivergent heterocycle synthesis from hetero-substituted enyne.

Project description:Diastereodivergent heterocycle synthesis has been recognized as an important tool for drug discovery in recent years, yet strategies based on nickelacycle formation have not been established. Here, we report a NHC-Ni catalyzed highly 1,3- and 1,4-diastereodivergent heterocycle synthesis from enyne, which is achieved by manipulating the enyne N-substituent (allowing switching of selectivity from up to 2:98 to 98:2). The key to success is the efficient diastereodivergent formation of a nickelacyclopentene, with broad enyne scope at mild conditions, which subsequently provides reductive hydroalkenylation, acylation and silylation products on demand. Diastereoisomers which are sterically hard to distinguish or difficult to access by conventional routes are now accessible easily, including those with very similar 4°, contiguous and skipped stereocenters.

| S-EPMC9814851 | biostudies-literature

Total synthesis of enantiopure (+)-gamma-lycorane using highly efficient Pd-catalyzed asymmetric allylic alkylation.

Project description:[reaction: see text] A highly efficient short total synthesis of (+)-gamma-lycorane (>99% ee, 41% overall yield) was achieved by using the asymmetric allylic alkylation in the key step catalyzed by palladium complexes with novel chiral biphenol-based monodentate phosphoramidite ligands.

| S-EPMC2562274 | 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