Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Reductive Rearrangement of a 1-Phospha-2-azanorbornene.

ABSTRACT: The reduction of the 1-phospha-2-azanorbornene derivate endo-1 with lithium aluminium hydride leads to an unprecedented 1-phosphabicyclo[3.2.1]octa-2,5-diene, while a phospholide anion is formed with lithium. The latter can be protonated resulting in formation of an unusual 2H-phosphole dimer. Furthermore, 3H-phospholes, previously assumed to have no synthetic relevance as intermediates, were proposed to act as dienophile in the dimerisation of 3,4-dimethyl-1-phenylphosphole at elevated temperatures based on theoretical calculations.

SUBMITTER: Wonneberger P

PROVIDER: S-EPMC8251630 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Reductive Rearrangement of a 1-Phospha-2-azanorbornene.

Wonneberger Peter P König Nils N Sárosi Menyhárt B MB Hey-Hawkins Evamarie E

Chemistry (Weinheim an der Bergstrasse, Germany) 20210503 29

The reduction of the 1-phospha-2-azanorbornene derivate endo-1 with lithium aluminium hydride leads to an unprecedented 1-phosphabicyclo[3.2.1]octa-2,5-diene, while a phospholide anion is formed with lithium. The latter can be protonated resulting in formation of an unusual 2H-phosphole dimer. Furthermore, 3H-phospholes, previously assumed to have no synthetic relevance as intermediates, were proposed to act as dienophile in the dimerisation of 3,4-dimethyl-1-phenylphosphole at elevated temperat ...[more]

PMID: 33780580

Similar Datasets

Lewis acid-catalyzed Pudovik reaction-phospha-Brook rearrangement sequence to access phosphoric esters.

Project description:Herein, we report a Lewis acid-catalyzed Pudovik reaction-phospha-Brook rearrangement sequence between diarylphosphonates or -phosphinates and α-pyridinealdehydes to access valuable phosphoric ester compounds. This transformation provides an extended substrate scope that is complementary to similar previously reported base-catalyzed transformations.

| S-EPMC9475178 | biostudies-literature

Reductive olefination of aldehydes via chromium Brook rearrangement.

Project description:[reaction: see text] The combination of CrCl(2) and silyl chlorides converts aryl and conjugated aldehydes into olefinic adducts in good to excellent yields. When constrained by structural features, the intermediate vic-diol can be isolated. Available data are consistent with a novel chromium Brook rearrangement.

| S-EPMC2517130 | biostudies-literature

Tandem Acid/Pd-Catalyzed Reductive Rearrangement of Glycol Derivatives.

Project description:Herein, we describe the acid/Pd-tandem-catalyzed transformation of glycol derivatives into terminal formic esters. Mechanistic investigations show that the substrate undergoes rearrangement to an aldehyde under [1,2] hydrogen migration and cleavage of an oxygen-based leaving group. The leaving group is trapped as its formic ester, and the aldehyde is reduced and subsequently esterified to a formate. Whereas the rearrangement to the aldehyde is catalyzed by sulfonic acids, the reduction step requires a unique catalyst system comprising a PdII or Pd0 precursor in loadings as low as 0.75?mol?% and ?,?'-bis(di-tert-butylphosphino)-o-xylene as ligand. The reduction step makes use of formic acid as an easy-to-handle transfer reductant. The substrate scope of the transformation encompasses both aromatic and aliphatic substrates and a variety of leaving groups.

| S-EPMC7154628 | biostudies-literature

Construction of vicinal 4°/3°-carbons <i>via</i> reductive Cope rearrangement.

Project description:Herein reported is a strategy for constructing vicinal 4°/3° carbons via reductive Cope rearrangement. Substrates have been designed which exhibit Cope rearrangement kinetic barriers of ∼23 kcal mol-1 with isoenergetic favorability (ΔG ∼ 0). These fluxional/shape-shifting molecules can be driven forward by chemoselective reduction to useful polyfunctionalized building blocks.

| S-EPMC8848919 | biostudies-literature

Single-Pot Reductive Rearrangement of Furfural to Cyclopentanone over Silica-Supported Pd Catalysts.

Project description:Direct one-pot hydrogenation of furfural (FFR) to cyclopentanone (CPO) was investigated over different silica-supported Pd catalysts. Among these, 4% Pd on fumed silica (4%Pd/f-SiO2) showed remarkable results, achieving almost 98% furfural (FFR) conversion with ∼89% selectivity and 87% yield to cyclopentanone at 165 °C and 500 psig H2 pressure. More interestingly, the fumed-silica-supported catalyst tuned the selectivity toward the rearrangement product, i.e., cyclopentanone, whereas all of the other supports were found to give ring hydrogenation as well as side chain hydrogenation products due to their parent Brönsted acidity and specific support properties. X-ray diffraction data revealed the presence of different phases of the face-centered cubic lattice of metallic Pd along with lowest crystallite size of 15.6 nm in the case of the silica-supported Pd catalyst. However, Pd particle size was found to be in the range of 5-13 nm with even dispersion over the silica support, confirmed by high-resolution transmission electron microscopy analysis. While studying the effect of reaction parameters, it was observed that lower temperature gave low furfural conversion of 58% with only 51% CPO selectivity. Similarly, higher H2 pressure lowered CPO selectivity with subsequent increase in 2-methyl furan and ring hydrogenation product 2-methyl furan and 2-methyl tetrahydrofuran. Thus, as per the requirement, the product selectivity can be tuned by varying the type of support and/or the reaction parameters suitably. With the help of several control experiments and the characterization data, a plausible reaction pathway was proposed for the selective formation of cyclopentanone.

| S-EPMC6644560 | biostudies-literature

The Phospha-Bora-Wittig Reaction.

Project description:We report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P═B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-Phosphaboraoxetanes undergo thermal or Lewis acid-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.

| S-EPMC8431359 | biostudies-literature

Phospha-bicyclohexene-germylenes exhibiting unexpected reactivity.

Project description:Introducing phospha-bicyclohexene (BCH)-germylenes (BCHGe's) as a novel, multifunctional compound class: the title compounds 15-18 are obtained from simple salt metathesis reactions of dipotassium germacyclopentadienediides K2[1] with phosphorusdichlorides. The BCHGe's 15-18 are stabilized by homoconjugation of the germanium(ii) centre with the remote C[double bond, length as m-dash]C double bond. Despite substantial thermodynamic stabilization, phospha-BCHGe's are reactive and undergo a reductive elimination of elemental germanium to give the corresponding phospholes. The elimination is a nucleophilic, bimolecular process and is prevented by large substituents. The reaction of phospha-BCHGe's with small electrophiles gives the corresponding phosphonium salts. Oxidation with chalcogens takes place at both the germanium and the phosphorus atom, and after elimination of germanium chalcogenides the corresponding phosphole chalcogenides were isolated. The introduced germylenes exhibit strong nucleophilic but also non-neglectable electrophilic properties.

| S-EPMC11310892 | biostudies-literature

Mechanism of the phospha-Wittig-Horner reaction.

Project description: Not available

| S-EPMC3738942 | biostudies-literature

Formation, Reactivity and Decomposition of Aryl Phospha-Enolates.

Project description:Two lithium phospha-enolates [RP=C(Sii Pr3 )OLi]2 were prepared by reaction of triisopropyl silyl phosphaethynolate, i Pr3 SiPCO, with aryl lithium reagents LiR (R=Mes: 1,3,5-trimethyl phenyl; or Mes*: 1,3,5,-tri-tertbutyl phenyl). Monomer/dimer aggregation of the enolates can be modulated by addition of 12-crown-4. Substitution of lithium for a heavier alkali metal was achieved through initial formation of a silyl enol ether, followed by reaction with KOt Bu to form the corresponding potassium phospha-enolate [MesP=C(Sii Pr3 )OK]2 . On addition of water, the enolates are protonated to afford RP=C(Sii Pr3 )(OH). For the sterically less demanding system (R=Mes), this phospha-enol rapidly tautomerises to the corresponding acyl phosphine MesP(H)C(Sii Pr3 )(O), which on heating extrudes CO. In contrast, bulkier phospha-enol (R=Mes*) is stable to rearrangement at room temperature and thermally decomposes to RH and i Pr3 SiPCO.

| S-EPMC10108052 | biostudies-literature

Lipase-Catalyzed Phospha-Michael Addition Reactions under Mild Conditions.

Project description:Organophosphorus compounds are the core structure of many active natural products. The synthesis of these compounds is generally achieved by metal catalysis requiring specifically functionalized substrates or harsh conditions. Herein, we disclose the phospha-Michael addition reaction of biphenyphosphine oxide with various substituted β-nitrostyrenes or benzylidene malononitriles. This biocatalytic strategy provides a direct route for the synthesis of C-P bonds with good functional group compatibility and simple and practical operation. Under the optimal conditions (styrene (0.5 mmol), biphenyphosphine oxide (0.5 mmol), Novozym 435 (300 U), and EtOH (1 mL)), lipase leads to the formation of organophosphorus compounds in yields up to 94% at room temperature. Furthermore, we confirm the role of the catalytic triad of lipase in this phospha-Michael addition reaction. This new biocatalytic system will have broad applications in organic synthesis.

| S-EPMC9698776 | 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