Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Substituents Regulate the Cyclization of Conjugated Alkynes to Accurately Construct Cyclo-(E)-[3]dendralenes.

ABSTRACT: Substituent-regulated cyclization of conjugated alkynes with acid catalysis was developed in this paper, and it provides a straightforward synthesis of cyclic-(E)-[3]dendralenes. Depending on the electronic effect of the aromatic ring pairing, a variety of phosphinyl quintuplet/hexa cyclo-[3]dendralenes with diverse substitution patterns are accessible, with good efficiency and high stereoselectivity. This self-cyclization process achieves the first precise construction of a phosphinylcyclo-(E)-[3]dendralene from conjugated alkynes to aromatization.

SUBMITTER: Xia YT

PROVIDER: S-EPMC10254459 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Substituents Regulate the Cyclization of Conjugated Alkynes to Accurately Construct Cyclo-(E)-[3]dendralenes.

Xia Yun-Tao YT Li Ya-Xin YX Bi Tong-Tong TT Lian Wei W Wang Xia X Yan Meng M Guo Tao T

Molecules (Basel, Switzerland) 20230527 11

Substituent-regulated cyclization of conjugated alkynes with acid catalysis was developed in this paper, and it provides a straightforward synthesis of cyclic-(E)-[3]dendralenes. Depending on the electronic effect of the aromatic ring pairing, a variety of phosphinyl quintuplet/hexa cyclo-[3]dendralenes with diverse substitution patterns are accessible, with good efficiency and high stereoselectivity. This self-cyclization process achieves the first precise construction of a phosphinylcyc ...[more]

PMID: 37298858

Similar Datasets

Hydroalkynylative cyclization of 1,6-enynes with terminal alkynes.

Project description:A rhodium-catalyzed highly regio- and enantioselective hydroalkynylation, generating cis-hydrobenzofuranone-tethered enynes has been developed. The reaction proceeds with a selective head-to-head insertion and symmetry breaking Michael addition cascade. One product was produced from tens of possible isomers through precise control of chemo-, regio-, and stereoselectivities using a single rhodium catalyst. Notable features of this method include 100% atom-economy, mild reaction conditions and a very broad substrate scope.

| S-EPMC6657412 | biostudies-literature

Rh-catalyzed aerobic oxidative cyclization of anilines, alkynes, and CO.

Project description:Transition-metal-catalyzed oxidative C-H cyclization of anilines has been an attractive and powerful strategy for the efficient construction of N-heterocycles. However, primary and tertiary anilines are rarely employed in this strategy due to the relative instability with strong oxidants or the presence of three C-N bonds. We describe here a novel Rh-catalyzed C-H cyclization of a wide range of anilines with alkynes and CO, using an aerobic oxidative protocol. Particularly, the simple primary anilines and readily prepared tertiary anilines could be easily converted to quinolin-2(1H)-ones, which are high value-added, biologically significant N-heterocycles, via C-N bond cleavage.

| S-EPMC5628386 | biostudies-literature

Tandem cyclization of alkynes via rhodium alkynyl and alkenylidene catalysis.

Project description:A rhodium(I)-catalyzed tandem cyclization of alkynes has been developed. The reaction allows for multiple bond formations to occur at both the alpha- and beta-positions of alkynes under mild conditions to yield a variety of fused ring systems as the products. In the presence of triethylamine and the complex derived from [Rh(COD)Cl]2 and P(4-F-C6H4)3, a terminal alkyne is converted to a rhodium alkynyl species which reacts with a tethered alkyl halide at the beta-position to provide a beta,beta-disubstituted alkenylidene complex. The rhodium alkenylidene species then undergoes additional ring closures with a range of pendent functional groups such as alkene, hydroxyl, and phenyl groups through [2 + 2] cycloaddition, nucleophilic addition, and 6pi-electrocyclization processes, respectively.

| S-EPMC1762102 | biostudies-literature

Synthesis of naphthalenes and 2-naphthols by the electrophilic cyclization of alkynes.

Project description:[reactions: see text] A wide variety of substituted naphthalenes are readily prepared regioselectively under mild reaction conditions by the 6-endo-dig electrophilic cyclization of appropriate arene-containing propargylic alcohols by ICl, I2, Br2, NBS, and PhSeBr. 3-Iodo-2-naphthols have also been prepared in excellent yields by the cyclization of analogous 1-aryl-3-alkyn-2-ones. This methodology readily accommodates various functional groups and has been successfully extended to the synthesis of substituted carbazoles and dibenzothiophenes.

| S-EPMC2532853 | biostudies-literature

A general synthesis of dendralenes.

Project description:The first general synthetic approach to substituted [3]- and higher dendralenes is reported. Fifty-one mono- through to penta-substituted dendralenes carrying alkyl-, cycloalkyl-, alkenyl-, alkynyl-, aryl- and heteroaryl-substitutents are accessed, and the first (E)/(Z)-stereoselective syntheses of dendralenes are reported (twenty-eight examples). The approach involves twofold Pd(0)-catalyzed Negishi couplings of 1,1-dibromoalkenes with alkenylzinc reagents, and exploits both substrate- and catalyst-controlled aspects of chemo-, regio- and stereoselectivity in the two C(sp2)-C(sp2) bond forming steps. The value of the new hydrocarbons in rapid structural complexity generation is demonstrated through their deployment in unprecedented diene- and triene-transmissive pericyclic reaction sequences.

| S-EPMC7003925 | biostudies-literature

Highly selective addition of cyclosilanes to alkynes enabling new conjugated materials.

Project description:Main group organometallic compounds can exhibit unusual optical properties arising from hybrid σ,π-conjugation. While linear silanes are extensively studied, the shortage of methods for the controlled synthesis of well-defined cyclic materials has precluded the study of cyclic conjugation. Herein we report that Ru-catalyzed addition of cyclosilanes to aryl acetylenes (hydrosilylation) proceeds with high chemoselectivity, regioselectivity, and diastereoselectivity, affording complex organosilanes that absorb visible light. We further show that the hydrosilylation products are useful building blocks towards novel conjugated polymers.

| S-EPMC9241958 | biostudies-literature

Formal synthesis of (-)-kendomycin featuring a Prins-cyclization to construct the macrocycle.

Project description:The kendomycin skeleton was prepared by a highly convergent strategy in which the benzofuran fragment and the acyclic iodide fragment were prepared by standard methods and joined using a Suzuki coupling. The distinctive reaction in our approach was an intramolecular Prins cyclization that assembles the macrocyclic ring in good yield. Modeling studies demonstrate that the acyclic chain is predisposed for macrocycle formation. Ultimately, the product was correlated with one of Lee's advanced intermediates for a formal total synthesis of kendomycin.

| S-EPMC2697922 | biostudies-literature

Direct Electrooxidative Selenylation/Cyclization of Alkynes: Access to Functionalized Benzo[b]furans.

Project description:A mild, practical, metal and oxidant-free methodology for the synthesis of various C-3 selenylated benzo[b]furan derivatives was developed through the intramolecular cyclization of alkynes promoted with diselenides via electrooxidation. A wide range of selenium-substituted benzo[b]furan derivatives were obtained in good to excellent yields with high regioselectivity under constant current in an undivided cell equipped with carbon and platinum plates as the anode and cathode, respectively. Moreover, the convergent approach exhibited good functional group tolerance and could be easily scaled up with good efficiency, providing rapid access to a diverse range of selenylated benzo[b]furans derivatives from simple, readily available starting materials.

| S-EPMC9572441 | biostudies-literature

Molecular engineering enabling reversible transformation between helical and planar conformations by cyclization of alkynes.

Project description:Molecular engineering enabling reversible transformation between helical and planar conformations is described herein. Starting from easily available 2-(pyridin-2-yl)anilines and alkynes, a one-pot strategy is set up for the synthesis of aza[4]helicenes via two successive rhodium-catalyzed C-H activation/cyclizations. Helical pyrrolophenanthridiziniums can be transformed into planar conformations through the cleavage of acidic pyrrole N-H, leading to turn-off fluorescence. NMR spectra, single crystal X-ray diffraction and DFT calculations demonstrate that the formation of an intramolecular C-H⋯N hydrogen bond is beneficial to stabilize the pyrrole nitrogen anion of the planar molecule and provide increased planarity. The reversible conformation transformations can be finely adjusted by the electron-donating and -withdrawing groups on the π+-fused pyrrole skeleton in the physiological pH range, thus affording an opportunity for pH-controlled intracellular selective fluorescence imaging. Pyrrolophenanthridiziniums show turn-on fluorescence in lysosomes owing to the acidic environment of lysosomes and turn-off fluorescence out of lysosomes, indicating the occurrence of the deprotonation reaction outside lysosomes and the corresponding transformation from helical to planar conformations.

| S-EPMC8179297 | biostudies-literature

Palladium(ii)-catalyzed synthesis of indenones through the cyclization of benzenecarbaldehydes with internal alkynes.

Project description:The palladium(ii)-catalyzed carbocyclization of benzenecarbaldehydes with internal alkynes to afford 2,3-disubstituted indenones was reported. The annulation reaction proceeded through the transmetalation of Pd(ii) with an aromatic aldehyde and the insertion of internal alkynes, followed by cyclization via the intramolecular nucleophilic addition of intermediate organopalladium(ii) species to the aldehyde group. This reaction proceeded in moderate to good yields with high regioselectivity.

| S-EPMC9072296 | biostudies-literature