Jeong-Yu Son

Rhodium-catalyzed oxidative coupling through C–H activation and annulation directed by phosphonamide and phosphinamide groups

Rhodium-catalyzed oxidative coupling reactions via C-H activation and annulation directed by phosphonamide and phosphinamide groups were developed under aerobic conditions, which produced benzazaphosphole 1-oxides and phosphaisoquinolin-1-oxides.

Synthesis of Cinnolin-3(2H)-one Derivatives from Rh-Catalyzed Reaction of Azobenzenes with Diazotized Meldrum’s Acid

A synthetic method of a wide range of cinnolin-3(2H)-one derivatives is developed from the reaction of symmetrical as well as unsymmetrical azobenzenes with diazotized Meldrums acid via Rh-catalyzed C-H alkylation followed by cyclization.

Synthesis of 2-Bromoimidazoles from Alkynes, N-Sulfonylazides, and Bromocyanides

A synthetic method for 2-bromoimidazoles is developed from Rh-catalyzed cyclization of N-sulfonyl-1,2,3-triazoles with bromocyanides. Cu-catalyzed [3 + 2] cycloaddition followed by Rh-catalyzed cyclization starting from alkynes, N-sulfonylazides, and bromocyanides is also demonstrated for de novo synthesis of 2-bromoimidazoles in one pot. Moreover, this work was successfully employed to introduce diverse functional groups to the 2-position of imidazoles via cross-coupling reaction.

Synthesis of 1,2-Benzothiazines by a Rhodium-Catalyzed Domino C–H Activation/Cyclization/Elimination Process from S-Aryl Sulfoximines and Pyridotriazoles

A method for the synthesis of a large number of 1,2-benzothiazines bearing pyridyl as well as carbonyl groups is developed from rhodium-catalyzed carbene insertions into aromatic C-H bonds of S-aryl sulfoximines using pyridotriazoles by denitrogenative cyclization followed by the elimination of alcohols. The present method involves the N-H/C-H activation of simple alkyl aryl sulfoximines and has the advantages of a broad substrate scope, high functional group tolerance, and good regioselectivity.

Selective Rhodium-Catalyzed C–H Amidation of Azobenzenes with Dioxazolones under Mild Conditions

A synthetic method for a wide range of amidated azobenzenes is developed from the selective rhodium-catalyzed C-H amidation reaction of symmetrical as well as unsymmetrical azobenzenes with alkyl-, aryl-, and heteroaryl-substituted dioxazolones under mild conditions. Diamidation of azobenzenes and amidation of monoamidated azobenzenes were also demonstrated.

Synthesis of 2-Alkoxyaryl-2-aryl Enamines via Tandem Copper-Catalyzed Cycloaddition and Rhodium-Catalyzed Alkoxyarylation from Alkynes, N-Sulfonyl Azides, and Aryl Ethers

A synthetic route to a wide range of 2-alkoxyaryl-2-aryl enamines is developed from Rh-catalyzed alkoxyarylation of N-sulfonyl-4-aryl-1,2,3-triazoles with aryl ethers via the elimination of nitrogen molecule. In addition, 2-alkoxyaryl-2-aryl enamines are prepared via tandem Cu-catalyzed cycloaddition and Rh-catalyzed alkoxyarylation starting from alkynes, N-sulfonyl azides, and aryl ethers in one-pot.

Alkenylation of Phosphacoumarins via Aerobic Oxidative Heck Reactions and Their Synthetic Application to Fluorescent Benzophosphacoumarins

Alkenylation of phosphacoumarins is developed from the reaction of phosphacoumarins with a variety of activated as well as nonactivated alkenes via aerobic oxidative Heck reactions. In addition, 3-alkenylphosphacoumarins undergo an inverse electron demand Diels-Alder reaction (IEDDA) with enamines in situ generated from ketone and pyrrolidine followed by 1,2-elimination and a dehydrogenation, producing fluorescent benzophosphacoumarins.

Regioselective Synthesis of Dihydrothiophenes and Thiophenes via the Rhodium-Catalyzed Transannulation of 1,2,3-Thiadiazoles with Alkenes

A method for the regioselective synthesis of a wide range of dihydrothiophenes was developed from the rhodium-catalyzed transannulation of 1,2,3-thiadiazoles with aliphatic, aromatic, and heteroaromatic alkenes. Tandem rhodium-catalyzed transannulation of 1,2,3-thiadiazoles with alkenes followed by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) oxidation was also demonstrated for the one-pot regioselective synthesis of various thiophenes. Advantages of the present method include a broad substrate scope, wide functional group compatibility, and high regioselectivity.

Synthesis of Imidazopyridines via Copper-Catalyzed, Formal Aza-[3 + 2] Cycloaddition Reaction of Pyridine Derivatives with α-Diazo Oxime Ethers

The Cu-catalyzed, formal aza-[3 + 2] cycloaddition reaction of pyridine derivatives with α-diazo oxime ethers in trifluoroethanol was used to synthesize imidazopyridines via the release of molecular nitrogen and elimination of alcohol. These methods enabled modular synthesis of a wide range of N-heterobicyclic compounds such as imidazopyridazines, imidazopyrimidines, and imidazopyrazines with an α-imino Cu-carbenoid generated from the α-diazo oxime ethers and copper.

Synthesis of Multisubstituted Allenes, Furans, and Pyrroles via Tandem Palladium-Catalyzed Substitution and Cycloisomerization

A palladium-catalyzed propargyl substitution reaction of propargyl acetates with indium organothiolates is developed for the synthesis of multisubstituted allenyl sulfides. This procedure can be applied to the synthesis of multisubstituted furans and pyrroles via tandem palladium-catalyzed propargyl substitution and cycloisomerization reaction in one pot.