Palladium-Catalyzed Intermolecular Dehydrogenative Aminohalogenation of Alkenes under Molecular Oxygen: An Approach to Brominated Enamines

A novel and efficient palladium-catalyzed dehydrogenative aminohalogenation of alkenes with molecular oxygen as the sole oxidant has been developed. This protocol provides a valuable synthetic tool for the assembly of a wide range of brominated enamines under mild conditions, with unprecedented stereoselectivity and exceptional functional group tolerance. This attractive route for the synthesis of brominated enamines is of great significance due to the products’ versatile reactivity for further transformations

Palladium-Catalyzed Intermolecular Dehydrogenative Aminohalogenation of Alkenes under Molecular Oxygen: An Approach to Brominated Enamines

A novel and efficient palladium-catalyzed dehydrogenative aminohalogenation of alkenes with molecular oxygen as the sole oxidant has been developed. This protocol provides a valuable synthetic tool for the assembly of a wide range of brominated enamines under mild conditions, with unprecedented stereoselectivity and exceptional functional group tolerance. This attractive route for the synthesis of brominated enamines is of great significance due to the products’ versatile reactivity for further transformations

Palladium-Catalyzed Phthalazinone Synthesis Using Paraformaldehyde as Carbon Source

A palladium-catalyzed one-pot synthesis of phthalazinones from 2-halomethyl benzoates, paraformaldehyde, and aryl hydrazines is described. Various substituted phthalazinones were selectively obtained in good yields using paraformaldehyde as the cheap carbon source (CH)

Copper-Catalyzed Formal C–N Bond Cleavage of Aromatic Methylamines: Assembly of Pyridine Derivatives

An efficient copper-catalyzed C–N bond cleavage of aromatic methylamines was developed to construct pyridine derivatives. With neat conditions and facile operation, the fragment-assembling strategy affords a broad range of 2,4,6-trisubstituted pyridines in up to 95% yield from simple and readily available starting materials. Interestingly, when pyridin-2-yl methylamine was employed as the substrate, α-alkylation reaction of ketones readily occurred to give β-(pyridin-2-yl) ketones instead of the 2,4,6-trisubstituted pyridines

Metal-Free Synthesis of 2‑Aminobenzothiazoles via Aerobic Oxidative Cyclization/Dehydrogenation of Cyclohexanones and Thioureas

A metal-free process for the synthesis of 2-aminobenzothiazoles from cyclohexanones and thioureas has been developed using catalytic iodine and molecular oxygen as the oxidant under mild conditions. Various 2-aminobenzothiazoles, 2-aminonaphtho[2,1-<i>d</i>]thiazoles, and 2-aminonaphtho[1,2-d]thiazoles were prepared via this method in satisfactory yields

Hydrogen-Borrowing Reduction/Dehydrogenative Aromatization of Nitroarenes through Visible-Light-Induced Energy Transfer: An Entry to Pyrimidoindazoles and Carbazoles

Herein, we describe a novel visible-light-induced protocol for hydrogen-borrowing reduction/dehydrogenation aromatization/cyclization of nitroarenes by energy transfer. The present protocol does not require additional oxidants, hydrogen acceptors, and hydrogen evolution metal catalysts. The mechanistic studies demonstrated that the hydrogen-borrowing reduction/dehydrogenative aromatization process was initiated by the formation of active singlet species through efficient energy transfer of excited Ir[dF(CF3)ppy]2(dtbpy)PF6 to nitroarenes

Copper-Catalyzed Oxidative C(sp³)–H Functionalization for Facile Synthesis of 1,2,4-Triazoles and 1,3,5-Triazines from Amidines

A facile and versatile catalytic system involving copper catalyst, K₃PO₄ as the base, and O₂ as the oxidant has been developed to enable efficient synthesis of 2,4,6-trisubstituted and 2,6-disubstituted 1,3,5-triazines and 1,3-disubstituted 1,2,4-triazoles from amidines with trialkylamines, DMSO, and DMF as the reaction partners, respectively. This protocol features inexpensive metal catalyst, green oxidant, good functional group tolerance, and high regioselectivity, providing an efficient entry to those products that are challenging to prepare by traditional methods. A single-electron-transfer (SET) mechanism is proposed for these transformations

Palladium-Catalyzed Oxidative C–N Bond Coupling Involving a Solvent-Controlled Regioselective Bromination Process

Stereoselective palladium-catalyzed oxidative C–N bond coupling reactions between aromatic amines and alkenes involving a solvent-controlled regioselective bromination process under 1 atm of oxygen atmosphere are disclosed, providing easy access to two different brominated enamines. The addition of hydrogen peroxide (30% aq) as a co-oxidant in the system is crucial for the dehydrogenative aminohalogenation under molecular oxygen (1 atm), and in such a case, the C–N bond coupling/electrophilic bromination reaction cascade is proposed. Furthermore, the different reaction media leads to a switched regioselectivity of the process

Palladium-Catalyzed Oxidative Coupling of Aromatic Primary Amines and Alkenes under Molecular Oxygen: Stereoselective Assembly of (<i>Z</i>)‑Enamines

An efficient Pd-catalyzed oxidative coupling of aromatic primary amines and alkenes under molecular oxygen is disclosed. Under mild reaction conditions, it provides a rapid access to (<i>Z</i>)-enamine compounds with exceptional functional group tolerance and excellent regio- and stereoselectivity. This attractive route is of great significance due to its applicability to a wide range of aromatic primary amines, most of which could not be efficiently converted into enamines previously. Moreover, this protocol is scalable, and the resultant enamines could be conveniently transformed into a series of N-containing heterocyclics, thus illustrating its potential applications in synthetic and medicinal chemistry

Palladium-Catalyzed Oxidative Coupling of Aromatic Primary Amines and Alkenes under Molecular Oxygen: Stereoselective Assembly of (<i>Z</i>)‑Enamines

An efficient Pd-catalyzed oxidative coupling of aromatic primary amines and alkenes under molecular oxygen is disclosed. Under mild reaction conditions, it provides a rapid access to (<i>Z</i>)-enamine compounds with exceptional functional group tolerance and excellent regio- and stereoselectivity. This attractive route is of great significance due to its applicability to a wide range of aromatic primary amines, most of which could not be efficiently converted into enamines previously. Moreover, this protocol is scalable, and the resultant enamines could be conveniently transformed into a series of N-containing heterocyclics, thus illustrating its potential applications in synthetic and medicinal chemistry