O-alkynyl Anilines Research Articles

A Cascade Synthesis of Hetero-arylated Triarylmethanes Through a Double 5-endo-dig Cyclization Sequence.

A sequential two-step method for the synthesis of hetero-arylated triarylmethanes through a Ag-catalyzed sequential double cyclization-nucleophilic addition cascade is described. This methodology basically involves an initial 5-endo-dig cyclization of o-alkynyl anilines to provide 2-substituted indole derivatives, which then react with 2-(2-enynyl)-pyridines to afford indolizine-containing unsymmetrical triarylmethanes through another 5-endo-dig cyclization.

Copper-Catalyzed Three-Component Carboamination of Arynes: Expeditious Synthesis of o-Alkynyl Anilines and o-Benzoxazolyl Anilines.

A copper-catalyzed three-component reaction of in situ formed arynes, terminal alkynes, and O-benzoylhydroxylamines has been developed. By adjusting reaction conditions, the nucleophiles in this transformation can be extended from terminal alkynes to benzoxazoles. These procedures provide a modular and facile approach to o-alkynyl anilines and o-benzoxazolyl anilines from easily available substrates in only one step.

Unveiling reactive metal sites in a Pd pincer MOF: insights into Lewis acid and pore selective catalysis.

A porous Zr metal-organic framework, 1-PdBF4 [Zr6O4(OH)4(OAc)2.4{(PNNNP)Pd(MeCN)}2.4(BF4)2.4; PNNNP = 2,6-(HNPAr2)2C5H3N; Ar = p-C6H4CO2-], has been synthesized via postsynthetic oxidative I-/BF4- ligand exchange using NOBF4. 1-PdBF4 enjoys markedly superior catalytic activity and recyclability to its trifluoracetate-exchanged analogue, 1-PdTFA, for the intramolecular cyclization of o-alkynyl anilines and the carbonyl-ene cyclization of citronellal. Moreover, 1-PdBF4 demonstrates a rare example of pore selective catalysis for the cyclization of 2-ethynyl aniline.

Diversely Substituted Quinolines via Rhodium-Catalyzed Alkyne Hydroacylation.

The Rh-catalyzed hydroacylative union of aldehydes and o-alkynyl anilines leads to 2-aminophenyl enones, and onward to substituted quinolines. The mild reaction conditions employed in this chemistry result in a process that displays broad functional group tolerance, allowing the preparation of diversely substituted quinolines in high yields. Extension to the use of o-alkynyl nitro arenes as substrates leads to 2-nitrochalcones, from which both quinolines and quinoline N-oxides can be accessed.

Gold-catalyzed tandem cycloisomerization/functionalization of in situ generated α-oxo gold carbenes in water.

A gold-catalyzed tandem cycloisomerization/functionalization of in situ generated α-oxo gold carbenes in water has been developed, which provides ready access to highly functionalized indole derivatives from o-alkynyl anilines and ynamides. Importantly, gold serves dual catalytic roles to mediate both the cycloisomerization of o-alkynyl anilines and the intermolecular oxidation of ynamides at the same time, thus providing a new type of concurrent tandem catalysis. The use of readily available starting materials, a simple procedure, and mild reaction conditions are other notable features of this method.

Application of FeCl3/Diorganyl Diselenides to Cyclization of o-Alkynyl Anilines: Synthesis of 3-Organoselenyl-(N-methyl)indoles

In this manuscript we described the FeCl₃/diorganyl di­selenides promoted intramolecular cyclization of <i>o</i>-alkynyl anilines, as an alternative for the construction of functionalized 3-organoselenyl indoles. The cyclization reactions proceeded smoothly at room temperature in the presence of air giving the 3-organoselenyl indoles in good yields. Additionally, the 3-organo­selenyl indoles proved to be quite useful as synthetic intermediates for the construction of more functionalized indole units through a selenium–lithium exchange reaction followed by trapping the lithium intermediate with different electrophiles.

Tandem β-Enamino Ester Formation and Cyclization with o-Alkynyl Anilines Catalyzed by InBr3: Efficient Synthesis of β-(N-Indolyl)-α,β-unsaturated Esters

A tandem reaction providing beta-(N-indolyl)-alpha,beta-unsaturated esters from beta-keto esters and o-alkynyl anilines was developed. Z-Alkenes were selectively formed due to the stability of the beta-enamino ester as an intermediate of the reaction. This reaction includes the intermolecular beta-enamino ester formation and intramolecular cyclization catalyzed by InBr(3).