유은정 교수

C-H amination of N-aryl benzamides with O-benzoyl hydroxylamines has been achieved with either Pd(II) or Pd(0) catalysts. Furthermore, we demonstrate that secondary amines can be directly used with benzoyl peroxide in a one-pot procedure that proceeds via the in situ generation of the appropriate O-benzoyl hydroxylamines. This catalytic reaction provides a new disconnection for the convergent synthesis of tertiary and secondary arylalkyl amines starting from benzoic acids.

4-Substituted 1-(N-sulfonyl)-1,2,3-triazoles are selectively obtained by using the Cu-catalyzed azide–alkyne cycloaddition reaction with sulfonyl azides. Performing the reaction at 0 °C in chloroform in the presence of 2,6-lutidine and CuI as the catalyst effectively prevents the ketenimine pathway and provides convenient access to N-sulfonyltriazoles in good to excellent yields.

Pd(II)-catalyzed β-C(sp(3))-H carbonylation of N-arylamides under CO (1 atm) has been achieved. Following amide-directed C(sp(3))-H cleavage and insertion of CO into the resulting [Pd(II)-C(sp(3))] bond, intramolecular C-N reductive elimination gave the corresponding succinimides, which could be readily converted to 1,4-dicarbonyl compounds. This method was found to be effective with substrates containing α-hydrogen atoms and could be applied to effect methylene C(sp(3))-H carbonylation of cyclo

Combined analyses of experimental and computational studies on the Cu-catalyzed three-component reactions of sulfonyl azides, terminal alkynes and amines, alcohols, or water are described. A range of experimental data including product distribution ratio and trapping of key intermediates support the validity of a common pathway in the reaction of 1-alkynes and two distinct types of azides substituted with sulfonyl and aryl(alkyl) groups. The proposal that bimolecular cycloaddition reactions take

Dipolar cycloaddition is one of the most valuable methods for synthesizing various carbo- and heterocycles because multiple carbon–carbon and carbon–heteroatom bonds form in a single step. Thus, practical generation of new 1, n -dipoles and control of their reactivities are significant aspects of modern organic chemistry. Although it is quite challenging to handle short-lived 1, n -dipolar species, 1, n -dipolar cycloadditions have been impressively developed in recent years. Advancement of thei

Air-stable azomethine ylides with an unusual pattern of charge distribution were efficiently prepared via the rhodium-catalyzed reaction between pyridines and 1-sulfonyl-1,2,3-triazoles. This reaction allowed for the first example of the catalytic multicomponent [5 + 2] cycloaddition reactions, thus resulting in the formation of biologically active 1,4-diazepine compounds.

[reaction: see text] It is shown that N-sulfonylimidates can be efficiently prepared by a three-component coupling of terminal alkynes, sulfonyl azides, and alcohols with use of a copper catalyst and an amine base. The reaction is characterized by mild conditions, high selectivity, and tolerance with various functional groups. Facile transformation of imidates to amidines was also achieved by sodium cyanide. Additionally, a protocol for the extremely efficient Pd-catalyzed [3,3]-sigmatropic rear

A new type of Cu-catalyzed multicomponent reaction has been developed relying on the in situ generation of N-sulfonyl- or N-phosphorylketenimine intermediates, which are obtained from the cycloaddition of 1-alkynes and sulfonyl- or phosphoryl azides followed by ring-opening rearrangement of the initially formed copper triazole species. This facile and versatile route to ketenimines has led to develop a range of highly efficient multicomponent reactions by employing diverse nucleophiles such as a

A new type of intermolecular rhodium(II)-catalyzed [5+3] cycloaddition has been developed. This higher-order cycloaddition between pyridinium zwitterion 1,5-dipole equivalents and enol diazoacetates enables the formation of eight-membered heterocyclic skeletons, which are otherwise difficult to construct. The optimized cycloaddition occurs efficiently under mild conditions with a wide range of pyridinium zwitterions and with high functional-group tolerance.

It is revealed that 2-sulfonyliminoindolines can be efficiently synthesized by the Cu-catalyzed cyclization reaction of N-alkyl- or aryl-substituted 2-ethynylanilines with sulfonyl azides. This new route to the indoline derivatives is characterized by mild reaction conditions, facile introduction of functional groups at the 2-position of the indoline ring, and the wide substrate scope. Selective transformation of indoline to oxindole and isatin analogs is also demonstrated.

Durch eine kupferkatalysierte Cycloaddition von Alkinen mit Sulfonylaziden werden 4-substituierte 1-(N-Sulfonyl)-1,2,3-triazole selektiv erhalten. Die im Schema gezeigte Umsetzung umgeht den Ketenimin-Reaktionsweg und führt glatt und in guten Ausbeuten zu den N-Sulfonyltriazolen.

Alpha-aryl beta-hydroxy imidates are efficiently obtained by the four-component reaction of ethyl glyoxylates, aryl acetylenes, sulfonyl azides, and alcohols using a copper catalyst. The developed procedure is characterized by high selectivity, mild reaction conditions, a wide substrate scope, and an excellent functional group tolerance. Facile transformations of the obtained sulfonylimidate moiety to other carbonyl groups such as sulfonamides or esters were also demonstrated.

A metal-catalyst-free, mild, and efficient synthetic protocol for polycyclic 1,4-benzodiazepines via cascade [5 + 2]/[2 + 2] cycloadditions between pyridinium zwitterions and arynes is reported. Mechanistic experiments revealed that pyridinium zwitterions act as 1,5-dipoles in [5 + 2] cycloadditions with arynes for the construction of 1,4-benzodiazepines, which further undergo [2 + 2] cycloaddition resulting in the one-pot formation of one C-N bond and three C-C bonds.

C-N-coupled heterobiaryls were synthesized by sequential N-H functionalization reactions: stereoselective rhodium-catalyzed N-H insertion, followed by regioselective palladium-catalyzed C-H amination. Because of the good substrate scope and excellent selectivity, the developed method presents a novel approach for the synthesis of heterobiaryls, which are potent antibiotics.

A pyridinium zwitterion substrate is employed with two different types of transition metal catalysts to develop a regiodivergent cycloaddition. The pyridinium zwitterion is a highly reactive dipolar substrate that can undergo a dipolar cycloaddition with various reactants. It has multiple reaction sites, and the chemoselectivity is determined by the electronic demand of the catalyst–substrate complex. The reaction with nucleophilic Pd reagents affords fused N-heterocyclic compounds via regiosele