Jin-Heng Li

Palladium-Catalyzed Decarboxylative Coupling of Alkynyl Carboxylic Acids with Benzyl Halides or Aryl Halides

The synthesis of internal benzyl alkynes and 1,2-diarylalkynes has been developed via palladium-catalyzed decarboxylative coupling reactions of alkynyl carboxylic acids with benzyl chlorides or aryl halides. In the presence of Pd(OAc)(2) and Xphos (L3), alkynyl carboxylic acids smoothly underwent the reaction with various benzyl halides, providing the corresponding benzyl alkynes in moderate to good yields. It is noteworthy that the optimal conditions are compatible with a wide range of aryl halides including less active aryl chlorides.

CuI/I2-Promoted Electrophilic Tandem Cyclization of 2-Ethynylbenzaldehydes with ortho-Benzenediamines: Synthesis of Iodoisoquinoline-Fused Benzimidazoles

An efficient tandem route to the synthesis of iodoisoquinoline-fused benzimidazole derivatives including an iodocyclization strategy has been developed. In the presence of CuI, a variety of 2-ethynylbenzaldehydes underwent the tandem reaction with benzenediamines and iodine to afford the corresponding iodoisoquinoline-fused benzimidazoles in moderate to good yields.

Copper-catalyzed thiolation annulations of 1,4-dihalides with sulfides leading to 2-trifluoromethyl benzothiophenes and benzothiazoles.

Copper-catalyzed double thiolation reaction of 1,4-dihalides with sulfides has been developed for selectively synthesizing 2-trifluoromethyl benzothiophenes and benzothiazoles. In the presence of CuI, a variety of 2-halo-1-(2-haloaryl)-3,3,3-trifluoropropylenes smoothly underwent the thiolation annulation with Na(2)S to afford 2-trifluoromethyl benzothiophenes in moderate to good yields. Moreover, the conditions are compatible with N-(2-haloaryl)trifluoroacetimidoyl chlorides in the presence of NaHS and K(3)PO(4), leading to 2-trifluoromethyl benzothiazoles.

PdCl2-promoted electrophilic annulation of 2-alkynylphenol derivatives with disulfides or diselenides in the presence of iodine.

An efficient synthesis of 3-chalcogen-benzo[b]furans via palladium-promoted annulation reactions of 2-alkynylphenol derivatives with disulfides or diselenides and iodide has been developed. In the presence of I(2) and PdCl(2), both 3-sulfenylbenzofurans and 3-selenenylbenzofurans were selectively prepared from the cyclization of 2-alkynyanisoles with disulfides or diselenides in moderate to excellent yields.

Palladium-Catalyzed Intramolecular 5-exo-dig Hydroarylations of N-Arylpropiolamides: Thermodynamics-Controlled Stereoselective Synthesis of 3-Methyleneoxindoles

Palladium-catalyzed intramolecular hydroarylation of N-arylpropiolamides has been developed for the stereoselective synthesis of 3-(monosubstituted methylene)oxindoles. In the presence of Pd(OAc)(2) and dppf, a variety of N-arylpropiolamides successfully underwent the intramolecular hydroarylation reaction to afford the corresponding 3-(monosubstituted-methylene)oxindoles in moderate to excellent yields. It is noteworthy that the stereoselectivity of the reaction can be controlled by varying the reaction temperature.

Palladium-Catalyzed Oxidative Coupling of Trialkylamines with Aryl Iodides Leading to Alkyl Aryl Ketones

A new, simple method for selectively synthesizing alkyl aryl ketones has been developed by palladium-catalyzed oxidative coupling of trialkylamines with aryl iodides. In the presence of PdCl(2)(MeCN)(2), TBAB, and ZnO, a variety of aryl iodides underwent an oxidative coupling reaction with tertiary amines and water to afford the corresponding alkyl aryl ketones in moderate to excellent yields. It is noteworthy that this method is the first example of using trialkylamines as the carbonyl sources for constructing alkyl aryl ketone skeletons.

Palladium-catalyzed selective heck-type diarylation of allylic esters with aryl halides involving a β-OAc elimination process.

Palladium-catalyzed selective Heck-type diarylation of allylic esters with aryl halides has been developed. Allylic esters are reacted with aryl iodides to provide the corresponding 1,3-diaryl propenes through a β-OAc elimination process. It is noteworthy that the methodology can be applied in constructing the indole and benzofuran skeletons.

Palladium-catalyzed iodine-mediated electrophilic annulation of 2-(1-alkynyl)biphenyls with disulfides.

A palladium-catalyzed, iodine-mediated electrophilic annulation between 2-(1-alkynyl)biphenyl and disulfide has been developed. With the combination of PdCl(2) and I(2), a variety of 2-(1-alkynyl)biphenyls underwent electrophilic annulations with various disulfides successfully to afford the corresponding 9-sulfenyl phenanthrenes in moderate to excellent yields.