22 research outputs found
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(sp<sup>3</sup>)–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,
K<sub>3</sub>PO<sub>4</sub> as the base, and O<sub>2</sub> 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