Browse
Submit Data
Databases
API
Help

Dataset Information

25 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Reactivity Profiles of Diazo Amides, Esters, and Ketones in Transition-Metal-Free C-H Insertion Reactions.

ABSTRACT: Vinyl cations derived from diazo ketones participate in transition-metal-free C-H insertion reactions, but the corresponding amide and ester analog exhibit divergent reactivity profiles. Whereas cations formed from diazo ketones undergo a rearrangement and C-H insertion sequence, those from diazo amides do so less efficiently and tend to be competitively trapped before the insertion step occurs. Diazo esters undergo several rearrangement steps and fail to insert. DFT calculations reveal that this disparity stems from two factors: differing levels of electrostatic stabilization of the initially formed vinyl cation by the adjacent carbonyl oxygen and predistortion of the ketone and amide systems toward C-H insertion. The computational data is in strong agreement with experimental results, and this study explains how structural and electronic factors determine the outcome of reactions of diazo carbonyl-derived vinyl cations.

SUBMITTER: Cleary SE

PROVIDER: S-EPMC7059911 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Manganese-Catalyzed α-Alkylation of Ketones, Esters, and Amides Using Alcohols.

Project description:Herein we report the manganese-catalyzed C-C bond-forming reactions via α-alkylation of ketones, amides, and esters, using primary alcohols. β-Alkylation of secondary alcohols by primary alcohols to obtain α-alkylated ketones is also reported. The reactions are catalyzed by a ( i Pr-PNP)Mn(H)(CO)2 pincer complex under mild conditions in the presence of (catalytic) base liberating water (and H2 in the case of secondary alcohol alkylation) as the sole byproduct.

| S-EPMC6466737 | biostudies-literature

Highly selective transition-metal-free transamidation of amides and amidation of esters at room temperature.

Project description:Amide chemistry has an essential role in the synthesis of high value molecules, such as pharmaceuticals, natural products, and fine chemicals. Over the past years, several examples of transamidation reactions have been reported. In general, transition-metal-based catalysts or harsh conditions are employed for these transformations due to unfavorable kinetics and thermodynamics of the process. Herein, we report a significant advance in this area and present the general method for transition-metal-free transamidation of amides and amidation of esters by highly selective acyl cleavage with non-nucleophilic amines at room temperature. In contrast to metal-catalyzed protocols, the method is operationally-simple, environmentally-friendly, and operates under exceedingly mild conditions. The practical value is highlighted by the synthesis of valuable amides in high yields. Considering the key role of amides in various branches of chemical science, we envision that this broadly applicable method will be of great interest in organic synthesis, drug discovery, and biochemistry.

| S-EPMC6178361 | biostudies-literature

Triarylborane-Catalyzed Alkenylation Reactions of Aryl Esters with Diazo Compounds.

Project description:Herein we report a facile, mild reaction protocol to form carbon-carbon bonds in the absence of transition metal catalysts. We demonstrate the metal-free alkenylation reactions of aryl esters with ?-diazoesters to give highly functionalized enyne products. Catalytic amounts of tris(pentafluorophenyl)borane (10-20?mol?%) are employed to afford the C=C coupled products (31 examples) in good to excellent yields (36-87?%). DFT studies were used to elucidate the mechanism for this alkenylation reaction.

| S-EPMC7497215 | biostudies-literature

Rhodium-catalyzed intramolecular C-H insertion of alpha-aryl-alpha-diazo ketones.

Project description:Direct diazo transfer proceeds smoothly with alpha-aryl ketones. The derived alpha-aryl-alpha-diazo ketones cyclize efficiently with Rh catalysis to give the corresponding alpha-aryl cyclopentanones.

| S-EPMC3248813 | biostudies-literature

Sequential aldol condensation-transition metal-catalyzed addition reactions of aldehydes, methyl ketones, and arylboronic acids.

Project description:Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form ?-substituted ketones is described. By using the 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access ?-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step.

| S-EPMC3077042 | biostudies-literature

Intramolecular Carbene C-H Insertion Reactions of 2-Diazo-2-sulfamoylacetamides.

Project description:The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from chloroacetyl chloride and secondary amines through acylation followed by sequential treatments with sodium sulfite, phosphorus oxychloride, secondary amines, and 4-nitrobenzenesulfonyl azide. The results indicate that: (1) 2-diazo-N,N-dimethyl-2-(N,N-diphenylsulfamoyl)acetamide can take the formal aromatic 1,5-C-H insertion in its N-phenylsulfonamide moiety to afford the corresponding 1,3-dihydrobenzo[c]isothiazole-3-carboxamide 2,2-dioxide derivative; (2) no aliphatic C-H insertions occur for 2-diazo-2-(N,N-dialkylsulfamoyl)acetamides; and (3) for 2-diazo-N-phenyl-2-(N-phenylsulfamoyl)acetamides, the formal aromatic 1,5-C-H insertion in the N-phenylacetamide moiety is favorable to afford the corresponding 3-sulfamoylindolin-2-one derivatives as sole or major products. The intramolecular competitive aromatic 1,5-C-H insertion reactions of 2-diazo-2-sulfamoylacetamides with aryl groups on both amide and sulfonamide groups reveal that the N-aryl substituents on acetamide are more active than those on sulfonamide. The chemoselectivity is controlled by electronic effect of the aryl group.

| S-EPMC6680402 | biostudies-literature

A transition-metal-free & diazo-free styrene cyclopropanation.

Project description:An operationally simple and broadly applicable novel cyclopropanation of styrenes using gem-diiodomethyl carbonyl reagents has been developed. Visible-light triggered the photoinduced generation of iodomethyl carbonyl radicals, able to cyclopropanate a wide array of styrenes with excellent chemoselectivity and functional group tolerance. To highlight the utility of our photocyclopropanation, we demonstrated the late-stage functionalization of biomolecule derivatives.

| S-EPMC7017872 | biostudies-literature

Multicomponent Mannich reactions with boron enolates derived from diazo esters and 9-BBN.

Project description:Diazo esters, arylboranes, and carbamoyl imines undergo a 3-component Mannich condensation reaction. Catalyzed by Cu(II) salts, the reaction affords the corresponding isocyanate Mannich product: one that can be easily trapped in situ by other nucleophiles. The Mannich condensation corresponds to an α,α-disubstituted enolate addition to imines. The reaction was rendered asymmetric by using the (-)-phenylmenthol ester in good yield and selectivities.

| S-EPMC4671502 | biostudies-literature

Photoredox-Catalyzed Giese Reactions: Decarboxylative Additions to Cyclic Vinylogous Amides and Esters.

Project description:An effective strategy has been developed for the photoredox-catalyzed decarboxylative addition of cyclic amino acids to both vinylogous amides and esters leading to uniquely substituted heterocycles. The additions take place exclusively trans to the substituent present on the dihydropyridone ring affording stereochemical control about the new carbon-carbon bond. These reactions are operationally simplistic and afford the desired products in good to excellent isolated yields.

| S-EPMC8777773 | biostudies-literature

Metal-free catalytic enantioselective C-B bond formation: (pinacolato)boron conjugate additions to ?,?-unsaturated ketones, esters, Weinreb amides, and aldehydes promoted by chiral N-heterocyclic carbenes.

Project description:The first broadly applicable metal-free enantioselective method for boron conjugate addition (BCA) to ?,?-unsaturated carbonyls is presented. The C-B bond forming reactions are promoted in the presence of 2.5-7.5 mol % of a readily accessible C(1)-symmetric chiral imidazolinium salt, which is converted, in situ, to the catalytically active diastereo- and enantiomerically pure N-heterocyclic carbene (NHC) by the common organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu). In addition to the commercially available bis(pinacolato)diboron [B(2)(pin)(2)], and in contrast to reactions with the less sterically demanding achiral NHCs, the presence of MeOH is required for high efficiency. Acyclic and cyclic ?,?-unsaturated ketones, as well as acyclic esters, Weinreb amides, and aldehydes, can serve as suitable substrates; the desired ?-boryl carbonyls are isolated in up to 94% yield and >98:2 enantiomer ratio (er). Transformations are often carried out at ambient temperature. In certain cases, such as when the relatively less reactive unsaturated amides are used, elevated temperatures are required (50-66 °C); nonetheless, reactions remain highly enantioselective. The utility of the NHC-catalyzed method is demonstrated through comparison with the alternative Cu-catalyzed protocols; in cases involving a polyfunctional substrate, unique profiles in chemoselectivity are exhibited by the metal-free approach (e.g., conjugate addition vs reaction with an alkyne, allene, or aldehyde).

| S-EPMC3354020 | 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