Browse
Submit Data
Databases
API
Help

Dataset Information

28 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

CYCLOADDITION REACTIONS OF AZIDE, FURAN, AND PYRROLE UNITS WITH BENZYNES GENERATED BY THE HEXADEHYDRO-DIELS-ALDER (HDDA) REACTION.

ABSTRACT: Benzynes can be generated by the intramolecular thermal cycloisomerization of triynes-the title HDDA reaction. We report here that these can be trapped by cycloaddition reaction with trimethylsilyl azide (1,3-dipolar) or a furan or pyrrole (4+2 Diels-Alder).

SUBMITTER: Chen J

PROVIDER: S-EPMC4045115 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

CYCLOADDITION REACTIONS OF AZIDE, FURAN, AND PYRROLE UNITS WITH BENZYNES GENERATED BY THE HEXADEHYDRO-DIELS-ALDER (HDDA) REACTION.

Chen Junhua J Baire Beeraiah B Hoye Thomas R TR

Heterocycles 20140101 2

Benzynes can be generated by the intramolecular thermal cycloisomerization of triynes-the title HDDA reaction. We report here that these can be trapped by cycloaddition reaction with trimethylsilyl azide (1,3-dipolar) or a furan or pyrrole (4+2 Diels-Alder). ...[more]

PMID: 24910496

Similar Datasets

Competition between classical and hexadehydro-Diels-Alder (HDDA) reactions of HDDA triynes with furan.

Project description:We report here thermal reactions between furan and one of three related triyne substrates. Each triyne is capable of reacting initially in two modes: (i) unimolecular hexadehydro-Diels-Alder (HDDA) reaction or (ii) bimolecular Diels-Alder reaction between one of its alkynes with furan. The relative rates of these initial events are such that two of the substrates react essentially in only one of modes (i) or (ii). The third is intermediate in behavior; its bifurcation is dependent on the concentration of the furan reactant. These results teach, more generally, principles relevant to the design of efficient HDDA-based reaction cascades.

| S-EPMC4443927 | biostudies-literature

Reactions of Hexadehydro-Diels-Alder (HDDA)-Derived Benzynes with Thioamides: Synthesis of Dihydrobenzothiazino-Heterocyclics.

Project description:Reaction of thioamides (e.g., II) with benzynes generated by the hexadehydro-Diels-Alder (HDDA) cycloisomerization (e.g., I) produces dihydrobenzothiazines (e.g., III). It is postulated that the reaction proceeds via benzothietene (cf. IV) and o-thiolatoaryliminium (cf. V) intermediates and that the latter undergoes intramolecular 1,3-hydrogen atom migration to produce the penultimate isomeric iminium zwitterions VI.

| S-EPMC5629071 | biostudies-literature

Rates of hexadehydro-Diels-Alder (HDDA) cyclizations: impact of the linker structure.

Project description:The rates of the hexadehydro-Diels-Alder (HDDA) reaction of substrates containing, minimally, a 1,3,8-triyne subunit are reported. Several series of related substrates, differing in the nature of the three-atom tether that links the 1,3-diyne and diynophile, were examined. Seemingly small changes in substrate structure result in large differences in cyclization rate, spanning more than 8 orders of magnitude. The reactivity trends revealed by these studies should prove useful in guiding substrate design and choice of reaction conditions in future applications.

| S-EPMC4156263 | biostudies-literature

Reactions of hexadehydro-Diels-Alder benzynes with structurally complex multifunctional natural products.

Project description:An important question in organic chemistry concerns the extent to which benzynes-one of the classical reactive intermediates in organic chemistry-can react in discriminating fashion with trapping reagents. In particular, whether these species can react selectively with substrates containing multiple functional groups and possible sites of reactivity has remained unanswered. Natural products comprise a palette of multifunctional compounds with which to address this question. Here, we show that benzynes produced by the hexadehydro-Diels-Alder (HDDA) reaction react with many secondary metabolites with a preference for one among several pathways. Examples demonstrating such selectivity include reactions with: phenolics, through dearomatizing ortho-substitution; alkaloids, through Hofmann-type elimination; tropolone and furan, through cycloaddition; and alkaloids, through three-component fragmentation-coupling reactions. We also demonstrate that the cinchona alkaloids quinidine and quinine give rise to products (some in as few as three steps) that enable subsequent and rapid access to structurally diverse polyheterocyclic compounds. The results show that benzynes are quite discriminating in their reactivity-a trait perhaps not broadly enough appreciated.

| S-EPMC5624805 | biostudies-literature

Mechanistic Duality in Tertiary Amine Additions to Thermally Generated Hexadehydro-Diels-Alder Benzynes.

Project description:Reported here are studies directed at understanding the mechanism of tertiary amine addition to hexadehydro-Diels-Alder (HDDA)-generated benzynes. Tertiary amines are presumed to engage benzynes by generation of a zwitterionic intermediate. Simple trialkylamines undergo intermolecular protonation by a protic nucleophile to give an aryl ammonium intermediate that is then dealkylated. Amines containing acidified ?-protons undergo an intramolecular elimination to give the aniline and an alkene. Finally, amino alcohols react at either of their N- or O atoms, depending upon the extent of internal hydrogen bonding.

| S-EPMC5650509 | biostudies-literature

Intramolecular [4 + 2] trapping of a hexadehydro-Diels-Alder (HDDA) benzyne by tethered arenes.

Project description:We report here the efficient, intramolecular trapping in a Diels-Alder (DA) sense of thermally generated benzynes by one of two pendant arene rings. A more electron-rich ring (p-methoxyphenyl) reacted substantially faster than a simple phenyl ring, which was, in turn, slightly more reactive vs a 4-carbomethoxyphenyl ring. Photoinduced di-?-methane rearrangement of the initial DA adducts gave rise to unusual isomeric polycyclic adducts.

| S-EPMC4729866 | biostudies-literature

5-Hydroxyindoles by intramolecular alkynol-furan diels-alder cycloaddition.

Project description:A convergent approach provides a convenient access to synthetically and biologically useful 3,4-disubstituted 5-hydroxyindoles. The one-pot procedure uses microwave heating to initiate an intramolecular [4 + 2]-cycloaddition of an alkynol segment onto a furan followed by a fragmentation, aromatization, and N-Boc deprotection cascade. Yields range from 15 to 74%, with aromatic substituents providing better conversions. 4-Trimethylsilylated analogues undergo a 1,3-silatropic rearrangement to give the O-TMS ethers.

| S-EPMC3684082 | biostudies-literature

Photochemical Hexadehydro-Diels-Alder Reaction.

Project description:We demonstrate that the hexadehydro-Diels-Alder (HDDA) cycloisomerization reaction to produce reactive benzyne derivatives can be initiated photochemically. As with the thermal variant of the HDDA process, the reactive intermediates are formed in the absence of reagents or the resulting byproducts required for the generation of benzynes by traditional methods. This photo-HDDA (or h?-HDDA) reaction occurs at much lower temperatures (including even at -70 °C) than the thermal HDDA, but the benzynes produced behave in the same fashion with respect to their trapping reactions, suggesting they are of the same electronic state.

| S-EPMC6348472 | biostudies-literature

The hexadehydro-Diels-Alder reaction.

Project description:Arynes (aromatic systems containing, formally, a carbon-carbon triple bond) are among the most versatile of all reactive intermediates in organic chemistry. They can be 'trapped' to give products that are used as pharmaceuticals, agrochemicals, dyes, polymers and other fine chemicals. Here we explore a strategy that unites the de novo generation of benzynes-through a hexadehydro-Diels-Alder reaction-with their in situ elaboration into structurally complex benzenoid products. In the hexadehydro-Diels-Alder reaction, a 1,3-diyne is engaged in a [4+2] cycloisomerization with a 'diynophile' to produce the highly reactive benzyne intermediate. The reaction conditions for this simple, thermal transformation are notable for being free of metals and reagents. The subsequent and highly efficient trapping reactions increase the power of the overall process. Finally, we provide examples of how this de novo benzyne generation approach allows new modes of intrinsic reactivity to be revealed.

| S-EPMC3538845 | biostudies-literature

The Aza-hexadehydro-Diels-Alder Reaction.

Project description:The generation of pyridynes from diyne nitriles is reported. These cyano-containing precursors are analogues of the triyne substrates typically used for the hexadehydro-Diels-Alder (HDDA) cycloisomerization reactions that produce ring-fused benzynes. Hence, the new processes described represent aza-HDDA reactions. Depending on the location of the nitrile, either 3,4-pyridynes (from 1,3-diynes containing a tethered cyano group) or 2,3-pyridynes (from 1-cyanoethyne derivatives containing a tethered alkyne) are produced. In situ trapping of these reactive intermediates leads to highly substituted and functionalized pyridine derivatives. In several instances, unprecedented pyridyne trapping reactions are seen. Differences in reaction energetics between the aza-HDDA substrates and that of their analogous HDDA (triyne) substrates are discussed.

| S-EPMC6921493 | 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