Jiuxi Chen

Eco-friendly synthesis of 2,3-dihydroquinazolin-4(1H)-ones in ionic liquids or ionic liquid–water without additional catalyst

2,3-Dihydroquinazolin-4(1H)-ones have been synthesized in high to excellent yields through direct cyclocondensation of anthranilamides and aldehydes in ionic liquids (ILs) or one-pot three-component cyclocondensation of isatoic anhydrides, ammonium acetate and aldehydes in ionic liquid–water solvent system without the use of any additional catalyst.

Copper(II) Acetate-Catalyzed Addition of Arylboronic Acids to Aromatic Aldehydes

A novel copper-catalyzed protocol for the synthesis of carbinol derivatives has been developed. In the presence of copper(II) acetate and dppf, carbinol derivatives were prepared by the addition of arylboronic acids to aromatic aldehydes in good to excellent yields. Moreover, the rigorous exclusion of air or moisture is not required in these transformations.

Unexpected Copper-Catalyzed Cascade Synthesis of Quinazoline Derivatives

The first example of a copper-catalyzed cascade reaction of (2-aminophenyl)methanols with aldehydes using the combination of cerium nitrate hexahydrate and ammonium chloride has been developed, leading to a wide range of 2-substituted quinazolines in moderate to excellent yields. The efficiency of this transformation was demonstrated by compatibility with a wide range of functional groups. Thus, the method represents a convenient and practical strategy for synthesis of 2-substituted quinazoline derivatives.

Palladium-catalyzed aromatic esterification of aldehydes with organoboronic acids and molecular oxygen.

A palladium-catalyzed aromatic esterification reaction of aldehydes with arylboronic acids under an air atmosphere was achieved. This reaction tolerates many functional groups and provides aryl benzoate derivatives with yields ranging from moderate to good. Dioxygen takes part in the reaction and is crucial for this transformation.

Palladium-catalyzed addition of potassium aryltrifluoroborates to aliphatic nitriles: synthesis of alkyl aryl ketones, diketone compounds, and 2-arylbenzo[b]furans.

A palladium-catalyzed addition of potassium aryltrifluoroborates to aliphatic nitriles has been developed, leading to a wide range of alkyl aryl ketones with moderate to excellent yields. Moreover, several dinitriles (e.g., malononitrile, glutaronitrile, and adiponitrile) were applicable to this process for the construction of 1,3-, 1,5-, or 1,6-dicarbonyl compounds. The scope of the developed approach is successfully explored toward the one-step synthesis of 2-arylbenzo[b]furans via sequential addition and intramolecular annulation reactions. The methodology accepted a wide range of substrates and is applicable to library synthesis.

Highly regioselective ring-opening of epoxides with thiophenols in ionic liquids without the use of any catalyst

Clean thiolysis reaction of various epoxides in ionic liquids (ILs) without the use of any catalyst generates β-hydroxy sulfides in excellent yields (83–98%) with high regioselectivity and chemoselectivity under mild reaction conditions.

Ligand-free copper-catalyzed coupling of nitroarenes with arylboronic acids

The first example of copper-catalyzed coupling of nitroarenes with arylboronic acids was developed, providing diaryl ethers in moderate to excellent yields. The efficiency of this reaction was demonstrated by compatibility with a wide range of groups. Moreover, the rigorous exclusion of air/moisture is not required in these transformations. Thus, the method represents a simple and facile procedure to access diaryl ethers. Preliminary mechanistic experiments using deuterium labeling showed that the oxygen atom was derived from water.

The Coupling of Arylboronic Acids with Nitroarenes Catalyzed by Rhodium

The coupling of arylboronic acids with electron-deficient nitroarenes was realized for the first time by using a rhodium(I) catalyst under an air atmosphere, achieving unsymmetrical diaryl ethers with yields ranging from poor to good. From a deuterium labeling experiment, the oxygen atom is derived from ambient water. The efficiency of this reaction was demonstrated by its compatibility with fluoro, bromo, chloro, and trifluoromethyl groups.

Copper-Catalyzed Three-Component Reaction for Regioselective Aryl- and Heteroarylselenation of Indoles using Selenium Powder

A new and efficient copper-catalyzed C3 aryl- and heteroarylselenation of indoles employing selenium powder has been developed. The advantages of this chemistry involve the use of cheap selenating reagents, tolerance of a variety of functional groups, and practicality. In addition, this protocol has been further elaborated in an intramolecular phenylselenation of a (hetero) aryl C-H bond to construct an important motif of benzoselenopheno[3,2-b]indole. A preliminary mechanism study suggests that the reaction starts with a Ullman-type selenation between aryl iodides and selenium, followed by an oxidative cross-coupling with indole. The utility of this method has been demonstrated in an efficient gram-scale synthesis and an application to the synthesis of tubulin polymerization inhibitor.

Eco-Friendly Synthesis of 2-Substituted Benzothiazoles Catalyzed by Cetyltrimethyl Ammonium Bromide (CTAB) in Water

Uma serie de benzotiazois 2-substituidos foi sintetizada pela condensacao de 2-aminotiofenol com aldeidos (RCHO: R = Alquil, Aril, Heteroaril, 2-Arilformil) na presenca de quantidade catalitica de brometo de cetiltrimetil amonio (CTAB) em agua e sem adicao de solventes orgânicos e oxidantes. Assim, usando esse protocolo, 2-alquilbenzotiazois foram sintetizados em altos rendimentos e 2-arilformilbenzotiazois foram obtidos pela condensacao de 2-aminotiofenol com arilformil aldeidos pela primeira vez. A series of 2-substituted benzothiazoles have been synthesized by the condensation of 2-aminothiophenol with aldehydes (RCHO: R = Alkyl, Aryl, Heteroaryl, 2-Arylformyl) in the presence of a catalytic amount of cetyltrimethyl ammonium bromide (CTAB) “on water” by a onepot procedure without additional organic solvents and oxidants. Thereinto, 2-alkylbenzothiazoles were synthesized in high yields and 2-arylformylbenzothiazoles were obtained from the condensation of 2-aminothiophenol with arylformyl aldehydes for the first time using the present protocol.