Synthesis of Azepinoindoles via Rhodium-Catalyzed Formal Aza-[4 + 3] Cycloaddition Reaction of 3‑Diazoindolin-2-imines with 1,3-Dienes in One-Pot

Rhodium-catalyzed formal aza-[4 + 3] cycloaddition reaction of 3-diazoindolin-2-imines with 1,3-dienes was demonstrated for the synthesis of azepinoindoles in good to excellent yields in one-pot. First, rhodium-catalyzed [2 + 1] cycloaddition reaction smoothly took place to produce iminyl vinyl cyclopropane intermediate at room temperature in chlorobenzene for 1 h, which was thermally converted to azepinoindoles via aza-Cope rearrangement

Synthesis of Bicyclic Isothiazoles through an Intramolecular Rhodium-Catalyzed Transannulation of Cyanothiadiazoles

An intramolecular rhodium-catalyzed transannulation of readily available cyanothiadiazoles containing an ester, amide, or ether as a linker is described. It provides a wide range of bicyclic isothiazoles in good to excellent yields together with the release of molecular nitrogen. These results indicate that the carbon atom in the α-thiavinyl carbene is nucleophilic and that the sulfur atom is electrophilic

Synthesis of Bicyclic Isothiazoles through an Intramolecular Rhodium-Catalyzed Transannulation of Cyanothiadiazoles

An intramolecular rhodium-catalyzed transannulation of readily available cyanothiadiazoles containing an ester, amide, or ether as a linker is described. It provides a wide range of bicyclic isothiazoles in good to excellent yields together with the release of molecular nitrogen. These results indicate that the carbon atom in the α-thiavinyl carbene is nucleophilic and that the sulfur atom is electrophilic

One-Pot Synthesis of Indolizines via Sequential Rhodium-Catalyzed [2 + 1]-Cyclopropanation, Palladium-Catalyzed Ring Expansion, and Oxidation Reactions from Pyridotriazoles and 1,3-Dienes

An efficient, one-pot synthetic method for producing functionalized indolizine derivatives was developed via a Rh-catalyzed [2 + 1]-cyclopropanation, Pd-catalyzed ring expansion, and subsequent oxidation using manganese dioxide from pyridotriazoles and 1,3-dienes

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 <i>N</i>-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 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 <i>N</i>-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 Diaryl Ketones through Oxidative Cleavage of the C–C Double Bonds in <i>N</i>‑Sulfonyl Enamides

An oxidative cleavage of a C–C double bond is developed from the photochemical [2+2]-cycloaddition of diaryl <i>N</i>-tosyl enamides, aryl heteroaryl <i>N</i>-tosyl enamides, and <i>N</i>-tosyl cyclic enamides with singlet molecular oxygen, followed by a ring-opening reaction mediated by Cs₂CO₃ under air and sunlight without the use of photosesitizer, producing symmetrical and unsymmetrical diaryl, heterodiaryl, and cyclic ketones in good to excellent yields. Moreover, the oxidative cleavage of C–C triple bonds from 1-alkynes is demonstrated for the synthesis of symmetrical and unsymmetrical ketones from the Cu-catalyzed [3+2]-cycloaddition, Rh-catalyzed alkoxyarylation, photooxygenation, and ring-opening reaction in one-pot. Because the synthesis of the symmetrical and unsymmetrical diaryl and/or heterodiaryl ketones bearing an electron-donating group is not easy, the present method is notable