Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Allyl transfer to aldehydes and ketones by Bronsted acid activation of allyl and crotyl 1,3,2-dioxazaborolidines.

ABSTRACT: Alkyl dioxazaborolidines are air-stable and often crystalline organoboranes. A variety of Brønsted acids activate allyl dioxazaborolidines to generate reactive allyl-transfer reagents in situ. These reagents add to aldehydes and ketones to generate the corresponding alcohols in good yields under mild conditions. The E- and Z-crotyl reagents react diastereoselectively with aldehydes and ketones to produce anti and syn adducts, respectively, a result consistent with a cyclic transition state (type I mechanism).

SUBMITTER: Reilly MK

PROVIDER: S-EPMC3017000 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Allyl transfer to aldehydes and ketones by Brønsted acid activation of allyl and crotyl 1,3,2-dioxazaborolidines.

Reilly Maureen K MK Rychnovsky Scott D SD

Organic letters 20101101 21

Alkyl dioxazaborolidines are air-stable and often crystalline organoboranes. A variety of Brønsted acids activate allyl dioxazaborolidines to generate reactive allyl-transfer reagents in situ. These reagents add to aldehydes and ketones to generate the corresponding alcohols in good yields under mild conditions. The E- and Z-crotyl reagents react diastereoselectively with aldehydes and ketones to produce anti and syn adducts, respectively, a result consistent with a cyclic transition state (type ...[more]

PMID: 20942379

Similar Datasets

Chiral Bronsted acid-catalyzed allylboration of aldehydes.

Project description:The catalytic enantioselective allylation of aldehydes is a long-standing problem of considerable interest to the chemical community. We disclose a new high-yielding and highly enantioselective chiral Brønsted acid-catalyzed allylboration of aldehydes. The reaction is shown to be highly general, with a broad substrate scope that covers aryl, heteroaryl, alpha,beta-unsaturated, and aliphatic aldehydes. The reaction conditions are also shown to be effective for the catalytic enantioselective crotylation of aldehydes. We believe that the high reactivity of the allylboronate is due to protonation of the boronate oxygen by the chiral phosphoric acid catalyst.

| S-EPMC2928988 | biostudies-literature

Indium-mediated allylation of aldehydes, ketones and sulfonimines with 2-(alkoxy)allyl bromides.

Project description:2-(Alkoxy)propenyl bromides are readily prepared from 1,3-dibromo-2-propanol in a two-step sequence involving hydroxyl protection and sodium hydride-induced dehydrobromination. Indium-mediated allylation of aldehydes, ketones, and sulfonimines with 2-(alkoxy)propenyl bromides furnishes the corresponding homoallylic alcohols and sulfonamines in good yields. The products can be easily transformed into ?-hydroxy ketones and esters, as well as substituted dihydropyrans and protected ?-amino acids. Chiral 2-(alkoxy)propenyl halides, derived from (-)-menthol and D-glucal, furnish diastereomerically enriched products.

| S-EPMC2976063 | biostudies-literature

Enantioselective PCCP Bronsted acid-catalyzed aminalization of aldehydes.

Project description:Here we present an enantioselective aminalization of aldehydes catalyzed by Brønsted acids based on pentacarboxycyclopentadienes (PCCPs). The cyclization reaction using readily available anthranilamides as building blocks provides access to valuable 2,3-dihydroquinazolinones containing one stereogenic carbon center with good enantioselectivity (ee up to 80%) and excellent yields (up to 97%).

| S-EPMC8450961 | biostudies-literature

Photoredox activation for the direct β-arylation of ketones and aldehydes.

Project description:The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis.

| S-EPMC3723331 | biostudies-literature

Bronsted Acid-Mediated Domino One-Pot Dual C-C Bond Formation: Chemoselective Synthesis of Fused Tricyclic Ketones.

Project description:A chemoselective synthesis of fused novel tricyclic motifs via a facile domino intramolecular cyclization is presented. The strategy enables the formation of dual C-C bond via intramolecular Friedel-Crafts alkylation followed by acylation to accomplish fused tricyclic ketones. Significantly, these fused tricyclic compounds are ubiquitous and constitute major structural cores of natural products.

| S-EPMC6641420 | biostudies-literature

Silyl Anion Initiated Hydroboration of Aldehydes and Ketones.

Project description:Hydroboration is an emerging method for mild and selective reduction of carbonyl compounds. Typically, transition-metal or reactive main-group hydride catalysts are used in conjunction with a mild reductant such as pinacolborane. The reactivity of the main-group catalysts is a consequence of the nucleophilicity of their hydride ligands. Silicon hydrides are significantly less reactive and are therefore not efficient hydroboration catalysts. Here, a readily prepared silyl anion is reported to be an effective initiator for the reduction of aldehydes and ketones requiring mild conditions, low catalyst loadings and with a good substrate scope. The silyl anion it is shown to activate HBpin to generate a reactive borohydride in situ which reacts with aldehydes and ketones to afford the hydroboration product.

| S-EPMC7496802 | biostudies-literature

Activity and stability studies of H-transfer reduction reactions of aldehydes and ketones over aluminium isopropoxide heterogenised catalysts.

Project description:Aluminium isopropoxide Al(OiPr)3 immobilised on various mesoporous supports (SiO2, TiO2 and γ-Al2O3) was tested for H-transfer reductions of various aldehydes and ketones in the presence of 2-propanol as a sacrificial agent. The heterogenised catalysts were characterised by N2 physisorption, XRD, SEM-EDX, FTIR and ICP-OES. The characterisation results show a successful grafting of the homogeneous aluminium isopropoxide catalyst, covalently bound to the solid surface, with high dispersion over the mesoporous supports. The heterogenised catalysts show an excellent catalytic activity with high selectivity towards the desired alcohol product, with performances that are comparable with those of the homogeneous Al(OiPr)3 catalyst. Al(OiPr)3 grafted on SiO2 shows higher activity compared to γ-Al2O3 and TiO2 supported catalysts. The catalysts remain very active after 5 cycles of reuse and no leached Al(OiPr)3 was found in the reaction mixture, hence showing an excellent stability. The work reported here shows that it is possible to effectively immobilise catalytic functions, usually working in the homogeneous phase, over solid supports, with the resulting heterogenised catalysts keeping the same catalytic activity of the homogeneous counterpart and excellent stability, and with the advantage of being able to recycle and reuse them, without loss of catalytic materials.

| S-EPMC9706686 | biostudies-literature

Reductions of aldehydes and ketones with a readily available N-heterocyclic carbene borane and acetic acid.

Project description:Acetic acid promotes the reduction of aldehydes and ketones by the readily available N-heterocyclic carbene borane, 1,3-dimethylimidazol-2-ylidene borane. Aldehydes are reduced over 1-24 h at room temperature with 1 equiv of acetic acid and 0.5 equiv of the NHC-borane. Ketone reductions are slower but can be accelerated by using 5 equiv of acetic acid. Aldehydes can be selectively reduced in the presence of ketones. On a small scale, products are isolated by evaporation of the reaction mixture and direct chromatography.

| S-EPMC3629027 | biostudies-literature

Chiral Bronsted acid from a cationic gold(I) complex: catalytic enantioselective protonation of silyl enol ethers of ketones.

Project description:A chiral Brønsted acid has been developed from a cationic gold(I) disphosphine complex in the presence of alcoholic solvent and applied to the enantioselective protonation reaction of silyl enol ethers of ketones. Various optically active cyclic ketones were obtained in excellent yields and high enantioselectivities, including cyclic ketones bearing aliphatic substrates at the α-position. Furthermore, the application of this Brønsted acid was extended to the first Brønsted acid-catalyzed enantioselective protonation reaction of silyl enol ethers of acyclic substrates, regardless of their E/Z ratio.

| S-EPMC3161142 | biostudies-literature

Analyses of Aliphatic Aldehydes and Ketones in Carbonaceous Chondrites.

Project description:Aliphatic aldehydes and ketones are essential building blocks for the synthesis of more complex organic compounds. Despite their potentially key role as precursors of astrobiologically important molecules, such as amino acids and carboxylic acids, this family of compounds has scarcely been evaluated in carbonaceous chondrites. The paucity of such analyses likely derives from the low concentration of aldehydes and ketones in the meteorites and from the currently used chromatographic methodologies that have not been optimized for meteorite analysis. In this work, we report the development of a novel analytical method to quantify the molecular distribution and compound-specific isotopic analysis of 29 aliphatic aldehydes and ketones. Using this method, we have investigated the molecular distribution and 13C-isotopic composition of aldehydes and ketones in 10 carbonaceous chondrites from the CI, CM, CR, and CV groups. The total concentration of carbonyl compounds ranged from 130 to 1000 nmol g-1 of meteorite with formaldehyde, acetaldehyde, and acetone being the most abundant species in all investigated samples. The 13C-isotopic values ranged from -67 to +64‰ and we did not observe clear relationships between 13C-content and molecular weight. Accurately measuring the relative abundances, determining the molecular distribution, and isotopic composition of chondritic organic compounds is central in assessing both their formation chemistry and synthetic relationships.

| S-EPMC7330996 | 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